diff --git a/go.mod b/go.mod
index b9e42e0014e2f82e8f42c24a8f1dd7096831cfd8..c6f8f49b2b13a616dfddc1c4174f0326c235a05f 100644
--- a/go.mod
+++ b/go.mod
@@ -18,7 +18,7 @@ require (
 	golang.org/x/net v0.0.0-20210420072503-d25e30425868 // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 	google.golang.org/genproto v0.0.0-20210416161957-9910b6c460de // indirect
-	google.golang.org/grpc v1.38.0
+	google.golang.org/grpc v1.39.0
 	google.golang.org/protobuf v1.26.0
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
diff --git a/go.sum b/go.sum
index 07067a72acb4b327e6a4d94cb81b4c1b6e1e6965..9ade692b006b90d90d13853f1df0bd988e597cea 100644
--- a/go.sum
+++ b/go.sum
@@ -48,6 +48,7 @@ github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuy
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
+github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/apache/arrow/go/arrow v0.0.0-20200601151325-b2287a20f230/go.mod h1:QNYViu/X0HXDHw7m3KXzWSVXIbfUvJqBFe6Gj8/pYA0=
 github.com/apache/thrift v0.12.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/apache/thrift v0.13.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
@@ -81,6 +82,7 @@ github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDk
 github.com/cloudflare/golz4 v0.0.0-20150217214814-ef862a3cdc58/go.mod h1:EOBUe0h4xcZ5GoxqC5SDxFQ8gwyZPKQoEzownBlhI80=
 github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
+github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
 github.com/cockroachdb/cockroach-go v0.0.0-20190925194419-606b3d062051/go.mod h1:XGLbWH/ujMcbPbhZq52Nv6UrCghb1yGn//133kEsvDk=
 github.com/cockroachdb/datadriven v0.0.0-20190809214429-80d97fb3cbaa/go.mod h1:zn76sxSg3SzpJ0PPJaLDCu+Bu0Lg3sKTORVIj19EIF8=
@@ -124,6 +126,7 @@ github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.m
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/franela/goblin v0.0.0-20200105215937-c9ffbefa60db/go.mod h1:7dvUGVsVBjqR7JHJk0brhHOZYGmfBYOrK0ZhYMEtBr4=
@@ -235,6 +238,7 @@ github.com/grpc-ecosystem/go-grpc-middleware v1.0.1-0.20190118093823-f849b5445de
 github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0 h1:Ovs26xHkKqVztRpIrF/92BcuyuQ/YW4NSIpoGtfXNho=
 github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0/go.mod h1:8NvIoxWQoOIhqOTXgfV/d3M/q6VIi02HzZEHgUlZvzk=
 github.com/grpc-ecosystem/grpc-gateway v1.9.5/go.mod h1:vNeuVxBJEsws4ogUvrchl83t/GYV9WGTSLVdBhOQFDY=
+github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/hailocab/go-hostpool v0.0.0-20160125115350-e80d13ce29ed/go.mod h1:tMWxXQ9wFIaZeTI9F+hmhFiGpFmhOHzyShyFUhRm0H4=
 github.com/hashicorp/consul/api v1.3.0/go.mod h1:MmDNSzIMUjNpY/mQ398R4bk2FnqQLoPndWW5VkKPlCE=
 github.com/hashicorp/consul/sdk v0.3.0/go.mod h1:VKf9jXwCTEY1QZP2MOLRhb5i/I/ssyNV1vwHyQBF0x8=
@@ -442,6 +446,7 @@ github.com/prometheus/procfs v0.6.0/go.mod h1:cz+aTbrPOrUb4q7XlbU9ygM+/jj0fzG6c1
 github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
 github.com/remyoudompheng/bigfft v0.0.0-20190728182440-6a916e37a237/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
+github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/zerolog v1.13.0/go.mod h1:YbFCdg8HfsridGWAh22vktObvhZbQsZXe4/zB0OKkWU=
@@ -505,6 +510,7 @@ go.opencensus.io v0.22.0/go.mod h1:+kGneAE2xo2IficOXnaByMWTGM9T73dGwxeWcUqIpI8=
 go.opencensus.io v0.22.2/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.opencensus.io v0.22.3/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
 go.opencensus.io v0.22.4/go.mod h1:yxeiOL68Rb0Xd1ddK5vPZ/oVn4vY4Ynel7k9FzqtOIw=
+go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
 go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
@@ -595,6 +601,7 @@ golang.org/x/net v0.0.0-20200520182314-0ba52f642ac2/go.mod h1:qpuaurCH72eLCgpAm/
 golang.org/x/net v0.0.0-20200625001655-4c5254603344/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200707034311-ab3426394381/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200813134508-3edf25e44fcc/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
+golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20200904194848-62affa334b73/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.0.0-20201029221708-28c70e62bb1d/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
@@ -807,6 +814,7 @@ google.golang.org/genproto v0.0.0-20200312145019-da6875a35672/go.mod h1:55QSHmfG
 google.golang.org/genproto v0.0.0-20200331122359-1ee6d9798940/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200430143042-b979b6f78d84/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200511104702-f5ebc3bea380/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
+google.golang.org/genproto v0.0.0-20200513103714-09dca8ec2884/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200515170657-fc4c6c6a6587/go.mod h1:YsZOwe1myG/8QRHRsmBRE1LrgQY60beZKjly0O1fX9U=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 h1:+kGHl1aib/qcwaRi1CbqBZ1rk19r85MNUf8HaBghugY=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
@@ -839,11 +847,14 @@ google.golang.org/grpc v1.30.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM
 google.golang.org/grpc v1.31.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM8pak=
 google.golang.org/grpc v1.32.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM8pak=
 google.golang.org/grpc v1.33.1/go.mod h1:fr5YgcSWrqhRRxogOsw7RzIpsmvOZ6IcH4kBYTpR3n0=
+google.golang.org/grpc v1.36.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
 google.golang.org/grpc v1.36.1/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
 google.golang.org/grpc v1.37.0 h1:uSZWeQJX5j11bIQ4AJoj+McDBo29cY1MCoC1wO3ts+c=
 google.golang.org/grpc v1.37.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/grpc v1.38.0 h1:/9BgsAsa5nWe26HqOlvlgJnqBuktYOLCgjCPqsa56W0=
 google.golang.org/grpc v1.38.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
+google.golang.org/grpc v1.39.0 h1:Klz8I9kdtkIN6EpHHUOMLCYhTn/2WAe5a0s1hcBkdTI=
+google.golang.org/grpc v1.39.0/go.mod h1:PImNr+rS9TWYb2O4/emRugxiyHZ5JyHW5F+RPnDzfrE=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
@@ -876,6 +887,7 @@ gopkg.in/warnings.v0 v0.1.2/go.mod h1:jksf8JmL6Qr/oQM2OXTHunEvvTAsrWBLb6OOjuVWRN
 gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bli9HhUf9+ttbYbLASfIpnQbh74=
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/vendor/google.golang.org/grpc/.travis.yml b/vendor/google.golang.org/grpc/.travis.yml
deleted file mode 100644
index 5847d94e5512d7c51ba4ac879f521b8631024bab..0000000000000000000000000000000000000000
--- a/vendor/google.golang.org/grpc/.travis.yml
+++ /dev/null
@@ -1,42 +0,0 @@
-language: go
-
-matrix:
-  include:
-  - go: 1.14.x
-    env: VET=1 GO111MODULE=on
-  - go: 1.14.x
-    env: RACE=1 GO111MODULE=on
-  - go: 1.14.x
-    env: RUN386=1
-  - go: 1.14.x
-    env: GRPC_GO_RETRY=on
-  - go: 1.14.x
-    env: TESTEXTRAS=1
-  - go: 1.13.x
-    env: GO111MODULE=on
-  - go: 1.12.x
-    env: GO111MODULE=on
-  - go: 1.11.x  # Keep until interop tests no longer require Go1.11
-    env: GO111MODULE=on
-
-go_import_path: google.golang.org/grpc
-
-before_install:
-  - if [[ "${GO111MODULE}" = "on" ]]; then mkdir "${HOME}/go"; export GOPATH="${HOME}/go"; fi
-  - if [[ -n "${RUN386}" ]]; then export GOARCH=386; fi
-  - if [[ "${TRAVIS_EVENT_TYPE}" = "cron" && -z "${RUN386}" ]]; then RACE=1; fi
-  - if [[ "${TRAVIS_EVENT_TYPE}" != "cron" ]]; then export VET_SKIP_PROTO=1; fi
-
-install:
-  - try3() { eval "$*" || eval "$*" || eval "$*"; }
-  - try3 'if [[ "${GO111MODULE}" = "on" ]]; then go mod download; else make testdeps; fi'
-  - if [[ -n "${GAE}" ]]; then source ./install_gae.sh; make testappenginedeps; fi
-  - if [[ -n "${VET}" ]]; then ./vet.sh -install; fi
-
-script:
-  - set -e
-  - if [[ -n "${TESTEXTRAS}" ]]; then examples/examples_test.sh; security/advancedtls/examples/examples_test.sh; interop/interop_test.sh; make testsubmodule; exit 0; fi
-  - if [[ -n "${VET}" ]]; then ./vet.sh; fi
-  - if [[ -n "${GAE}" ]]; then make testappengine; exit 0; fi
-  - if [[ -n "${RACE}" ]]; then make testrace; exit 0; fi
-  - make test
diff --git a/vendor/google.golang.org/grpc/README.md b/vendor/google.golang.org/grpc/README.md
index 3949a683fb58ad6f3891416487e170663419870f..0e6ae69a58461ae7da5da9e53ca1578c0e65cb45 100644
--- a/vendor/google.golang.org/grpc/README.md
+++ b/vendor/google.golang.org/grpc/README.md
@@ -136,6 +136,6 @@ errors.
 [Go module]: https://github.com/golang/go/wiki/Modules
 [gRPC]: https://grpc.io
 [Go gRPC docs]: https://grpc.io/docs/languages/go
-[Performance benchmark]: https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5652536396611584&widget=490377658&container=1286539696
+[Performance benchmark]: https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5180705743044608
 [quick start]: https://grpc.io/docs/languages/go/quickstart
 [go-releases]: https://golang.org/doc/devel/release.html
diff --git a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
index 4cc7f9159b16e2c19864d0e967a5810b8c4ffe7f..dd8397963974a41dd38dca4eb7dc733bb8127e8e 100644
--- a/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
+++ b/vendor/google.golang.org/grpc/balancer_conn_wrappers.go
@@ -43,7 +43,8 @@ type ccBalancerWrapper struct {
 	cc         *ClientConn
 	balancerMu sync.Mutex // synchronizes calls to the balancer
 	balancer   balancer.Balancer
-	scBuffer   *buffer.Unbounded
+	updateCh   *buffer.Unbounded
+	closed     *grpcsync.Event
 	done       *grpcsync.Event
 
 	mu       sync.Mutex
@@ -53,7 +54,8 @@ type ccBalancerWrapper struct {
 func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
 	ccb := &ccBalancerWrapper{
 		cc:       cc,
-		scBuffer: buffer.NewUnbounded(),
+		updateCh: buffer.NewUnbounded(),
+		closed:   grpcsync.NewEvent(),
 		done:     grpcsync.NewEvent(),
 		subConns: make(map[*acBalancerWrapper]struct{}),
 	}
@@ -67,35 +69,53 @@ func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.Bui
 func (ccb *ccBalancerWrapper) watcher() {
 	for {
 		select {
-		case t := <-ccb.scBuffer.Get():
-			ccb.scBuffer.Load()
-			if ccb.done.HasFired() {
+		case t := <-ccb.updateCh.Get():
+			ccb.updateCh.Load()
+			if ccb.closed.HasFired() {
 				break
 			}
-			ccb.balancerMu.Lock()
-			su := t.(*scStateUpdate)
-			ccb.balancer.UpdateSubConnState(su.sc, balancer.SubConnState{ConnectivityState: su.state, ConnectionError: su.err})
-			ccb.balancerMu.Unlock()
-		case <-ccb.done.Done():
+			switch u := t.(type) {
+			case *scStateUpdate:
+				ccb.balancerMu.Lock()
+				ccb.balancer.UpdateSubConnState(u.sc, balancer.SubConnState{ConnectivityState: u.state, ConnectionError: u.err})
+				ccb.balancerMu.Unlock()
+			case *acBalancerWrapper:
+				ccb.mu.Lock()
+				if ccb.subConns != nil {
+					delete(ccb.subConns, u)
+					ccb.cc.removeAddrConn(u.getAddrConn(), errConnDrain)
+				}
+				ccb.mu.Unlock()
+			default:
+				logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", t, t)
+			}
+		case <-ccb.closed.Done():
 		}
 
-		if ccb.done.HasFired() {
+		if ccb.closed.HasFired() {
+			ccb.balancerMu.Lock()
 			ccb.balancer.Close()
+			ccb.balancerMu.Unlock()
 			ccb.mu.Lock()
 			scs := ccb.subConns
 			ccb.subConns = nil
 			ccb.mu.Unlock()
+			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
+			ccb.done.Fire()
+			// Fire done before removing the addr conns.  We can safely unblock
+			// ccb.close and allow the removeAddrConns to happen
+			// asynchronously.
 			for acbw := range scs {
 				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
 			}
-			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
 			return
 		}
 	}
 }
 
 func (ccb *ccBalancerWrapper) close() {
-	ccb.done.Fire()
+	ccb.closed.Fire()
+	<-ccb.done.Done()
 }
 
 func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) {
@@ -109,7 +129,7 @@ func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s co
 	if sc == nil {
 		return
 	}
-	ccb.scBuffer.Put(&scStateUpdate{
+	ccb.updateCh.Put(&scStateUpdate{
 		sc:    sc,
 		state: s,
 		err:   err,
@@ -150,17 +170,10 @@ func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer
 }
 
 func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
-	acbw, ok := sc.(*acBalancerWrapper)
-	if !ok {
-		return
-	}
-	ccb.mu.Lock()
-	defer ccb.mu.Unlock()
-	if ccb.subConns == nil {
-		return
-	}
-	delete(ccb.subConns, acbw)
-	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+	// The RemoveSubConn() is handled in the run() goroutine, to avoid deadlock
+	// during switchBalancer() if the old balancer calls RemoveSubConn() in its
+	// Close().
+	ccb.updateCh.Put(sc)
 }
 
 func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) {
diff --git a/vendor/google.golang.org/grpc/clientconn.go b/vendor/google.golang.org/grpc/clientconn.go
index 24109264f557c4312438e918e12f17fe6252c7f7..5cef39295bdcbbe43e4e74fb583baa3042c763b3 100644
--- a/vendor/google.golang.org/grpc/clientconn.go
+++ b/vendor/google.golang.org/grpc/clientconn.go
@@ -711,7 +711,12 @@ func (cc *ClientConn) switchBalancer(name string) {
 		return
 	}
 	if cc.balancerWrapper != nil {
+		// Don't hold cc.mu while closing the balancers. The balancers may call
+		// methods that require cc.mu (e.g. cc.NewSubConn()). Holding the mutex
+		// would cause a deadlock in that case.
+		cc.mu.Unlock()
 		cc.balancerWrapper.close()
+		cc.mu.Lock()
 	}
 
 	builder := balancer.Get(name)
@@ -1046,12 +1051,12 @@ func (cc *ClientConn) Close() error {
 
 	cc.blockingpicker.close()
 
-	if rWrapper != nil {
-		rWrapper.close()
-	}
 	if bWrapper != nil {
 		bWrapper.close()
 	}
+	if rWrapper != nil {
+		rWrapper.close()
+	}
 
 	for ac := range conns {
 		ac.tearDown(ErrClientConnClosing)
diff --git a/vendor/google.golang.org/grpc/go.mod b/vendor/google.golang.org/grpc/go.mod
index b177cfa66df52a7b40b5fba414daa970a56809a6..6eed9370b462eaa1a1088ecf39b816279f45f238 100644
--- a/vendor/google.golang.org/grpc/go.mod
+++ b/vendor/google.golang.org/grpc/go.mod
@@ -4,14 +4,14 @@ go 1.11
 
 require (
 	github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403
-	github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d
+	github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
-	github.com/golang/protobuf v1.4.2
+	github.com/golang/protobuf v1.4.3
 	github.com/google/go-cmp v0.5.0
 	github.com/google/uuid v1.1.2
-	golang.org/x/net v0.0.0-20190311183353-d8887717615a
-	golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be
-	golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a
+	golang.org/x/net v0.0.0-20200822124328-c89045814202
+	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
+	golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd
 	google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
 	google.golang.org/protobuf v1.25.0
 )
diff --git a/vendor/google.golang.org/grpc/go.sum b/vendor/google.golang.org/grpc/go.sum
index 24d2976abbafc5dafcbb57f274b948f106aeed4e..51fd1436e38f29d1b4583f21b93a4e38d086077b 100644
--- a/vendor/google.golang.org/grpc/go.sum
+++ b/vendor/google.golang.org/grpc/go.sum
@@ -1,32 +1,42 @@
-cloud.google.com/go v0.26.0 h1:e0WKqKTd5BnrG8aKH3J3h+QvEIQtSUcf2n5UZ5ZgLtQ=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+cloud.google.com/go v0.34.0 h1:eOI3/cP2VTU6uZLDYAoic+eyzzB9YyGmJ7eIjl8rOPg=
+cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/census-instrumentation/opencensus-proto v0.2.1 h1:glEXhBS5PSLLv4IXzLA5yPRVX4bilULVyxxbrfOtDAk=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403 h1:cqQfy1jclcSy/FwLjemeg3SR1yaINm74aQyupQ0Bl8M=
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
+github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed h1:OZmjad4L3H8ncOIR8rnb5MREYqG8ixi5+WbeUsquF0c=
+github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
-github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d h1:QyzYnTnPE15SQyUeqU6qLbWxMkwyAyu+vGksa0b7j00=
-github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0 h1:dulLQAYQFYtG5MTplgNGHWuV2D+OBD+Z8lmDBmbLg+s=
+github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/protoc-gen-validate v0.1.0 h1:EQciDnbrYxy13PgWoY8AqoxGiPrpgBZ1R8UNe3ddc+A=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b h1:VKtxabqXZkF25pY9ekfRL6a582T4P37/31XEstQ5p58=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
 github.com/golang/mock v1.1.1/go.mod h1:oTYuIxOrZwtPieC+H1uAHpcLFnEyAGVDL/k47Jfbm0A=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.3.3/go.mod h1:vzj43D7+SQXF/4pzW/hwtAqwc6iTitCiVSaWz5lYuqw=
 github.com/golang/protobuf v1.4.0-rc.1/go.mod h1:ceaxUfeHdC40wWswd/P6IGgMaK3YpKi5j83Wpe3EHw8=
 github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:xKAWHe0F5eneWXFV3EuXVDTCmh+JuBKY0li0aMyXATA=
 github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs=
 github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
 github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvqG2KuDX0=
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
-github.com/golang/protobuf v1.4.2 h1:+Z5KGCizgyZCbGh1KZqA0fcLLkwbsjIzS4aV2v7wJX0=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.4.3 h1:JjCZWpVbqXDqFVmTfYWEVTMIYrL/NPdPSCHPJ0T/raM=
+github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
 github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
@@ -35,49 +45,64 @@ github.com/google/go-cmp v0.5.0 h1:/QaMHBdZ26BB3SSst0Iwl10Epc+xhTquomWX0oZEB6w=
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
+go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be h1:vEDujvNQGv4jgYKudGeI/+DAX4Jffq6hpD55MmoEvKs=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20200822124328-c89045814202 h1:VvcQYSHwXgi7W+TpUR6A9g6Up98WAHf3f/ulnJ62IyA=
+golang.org/x/net v0.0.0-20200822124328-c89045814202/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
+golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d h1:TzXSXBo42m9gQenoE3b9BGiEpg5IG2JkU5FkPIawgtw=
+golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv3hCI0z56oJR5vAMgBU=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd h1:xhmwyvizuTgC2qz7ZlMluP20uW+C3Rm0FD/WLDX8884=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0 h1:/wp5JvzpHIxhs/dumFmF7BXTf3Z+dd4uXta4kVyO508=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
+google.golang.org/genproto v0.0.0-20200513103714-09dca8ec2884/go.mod h1:55QSHmfGQM9UVYDPBsyGGes0y52j32PQ3BqQfXhyH3c=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013 h1:+kGHl1aib/qcwaRi1CbqBZ1rk19r85MNUf8HaBghugY=
 google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013/go.mod h1:NbSheEEYHJ7i3ixzK3sjbqSGDJWnxyFXZblF3eUsNvo=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
 google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
 google.golang.org/grpc v1.25.1/go.mod h1:c3i+UQWmh7LiEpx4sFZnkU36qjEYZ0imhYfXVyQciAY=
 google.golang.org/grpc v1.27.0/go.mod h1:qbnxyOmOxrQa7FizSgH+ReBfzJrCY1pSN7KXBS8abTk=
+google.golang.org/grpc v1.33.1/go.mod h1:fr5YgcSWrqhRRxogOsw7RzIpsmvOZ6IcH4kBYTpR3n0=
+google.golang.org/grpc v1.36.0/go.mod h1:qjiiYl8FncCW8feJPdyg3v6XW24KsRHe+dy9BAGRRjU=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
@@ -90,7 +115,8 @@ google.golang.org/protobuf v1.25.0 h1:Ejskq+SyPohKW+1uil0JJMtmHCgJPJ/qWTxr8qp+R4
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.3 h1:fvjTMHxHEw/mxHbtzPi3JCcKXQRAnQTBRo6YCJSVHKI=
+gopkg.in/yaml.v2 v2.2.3/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
diff --git a/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go b/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go
index 200b115ca209ed7797628e3f068a647af97e7b10..7bc3583b5fcc1b4cd92444d900c5f22701c7ab27 100644
--- a/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go
+++ b/vendor/google.golang.org/grpc/internal/grpcrand/grpcrand.go
@@ -31,26 +31,30 @@ var (
 	mu sync.Mutex
 )
 
+// Int implements rand.Int on the grpcrand global source.
+func Int() int {
+	mu.Lock()
+	defer mu.Unlock()
+	return r.Int()
+}
+
 // Int63n implements rand.Int63n on the grpcrand global source.
 func Int63n(n int64) int64 {
 	mu.Lock()
-	res := r.Int63n(n)
-	mu.Unlock()
-	return res
+	defer mu.Unlock()
+	return r.Int63n(n)
 }
 
 // Intn implements rand.Intn on the grpcrand global source.
 func Intn(n int) int {
 	mu.Lock()
-	res := r.Intn(n)
-	mu.Unlock()
-	return res
+	defer mu.Unlock()
+	return r.Intn(n)
 }
 
 // Float64 implements rand.Float64 on the grpcrand global source.
 func Float64() float64 {
 	mu.Lock()
-	res := r.Float64()
-	mu.Unlock()
-	return res
+	defer mu.Unlock()
+	return r.Float64()
 }
diff --git a/vendor/google.golang.org/grpc/internal/transport/controlbuf.go b/vendor/google.golang.org/grpc/internal/transport/controlbuf.go
index f63a0137622aa85af1f7092bff3a575f9650683d..45532f8aeaab4def96bc8e44cd6a08ce7c397fcf 100644
--- a/vendor/google.golang.org/grpc/internal/transport/controlbuf.go
+++ b/vendor/google.golang.org/grpc/internal/transport/controlbuf.go
@@ -296,7 +296,7 @@ type controlBuffer struct {
 	// closed and nilled when transportResponseFrames drops below the
 	// threshold.  Both fields are protected by mu.
 	transportResponseFrames int
-	trfChan                 atomic.Value // *chan struct{}
+	trfChan                 atomic.Value // chan struct{}
 }
 
 func newControlBuffer(done <-chan struct{}) *controlBuffer {
@@ -310,10 +310,10 @@ func newControlBuffer(done <-chan struct{}) *controlBuffer {
 // throttle blocks if there are too many incomingSettings/cleanupStreams in the
 // controlbuf.
 func (c *controlBuffer) throttle() {
-	ch, _ := c.trfChan.Load().(*chan struct{})
+	ch, _ := c.trfChan.Load().(chan struct{})
 	if ch != nil {
 		select {
-		case <-*ch:
+		case <-ch:
 		case <-c.done:
 		}
 	}
@@ -347,8 +347,7 @@ func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it cbItem) (b
 		if c.transportResponseFrames == maxQueuedTransportResponseFrames {
 			// We are adding the frame that puts us over the threshold; create
 			// a throttling channel.
-			ch := make(chan struct{})
-			c.trfChan.Store(&ch)
+			c.trfChan.Store(make(chan struct{}))
 		}
 	}
 	c.mu.Unlock()
@@ -389,9 +388,9 @@ func (c *controlBuffer) get(block bool) (interface{}, error) {
 				if c.transportResponseFrames == maxQueuedTransportResponseFrames {
 					// We are removing the frame that put us over the
 					// threshold; close and clear the throttling channel.
-					ch := c.trfChan.Load().(*chan struct{})
-					close(*ch)
-					c.trfChan.Store((*chan struct{})(nil))
+					ch := c.trfChan.Load().(chan struct{})
+					close(ch)
+					c.trfChan.Store((chan struct{})(nil))
 				}
 				c.transportResponseFrames--
 			}
@@ -407,7 +406,6 @@ func (c *controlBuffer) get(block bool) (interface{}, error) {
 		select {
 		case <-c.ch:
 		case <-c.done:
-			c.finish()
 			return nil, ErrConnClosing
 		}
 	}
@@ -432,6 +430,14 @@ func (c *controlBuffer) finish() {
 			hdr.onOrphaned(ErrConnClosing)
 		}
 	}
+	// In case throttle() is currently in flight, it needs to be unblocked.
+	// Otherwise, the transport may not close, since the transport is closed by
+	// the reader encountering the connection error.
+	ch, _ := c.trfChan.Load().(chan struct{})
+	if ch != nil {
+		close(ch)
+	}
+	c.trfChan.Store((chan struct{})(nil))
 	c.mu.Unlock()
 }
 
diff --git a/vendor/google.golang.org/grpc/internal/transport/handler_server.go b/vendor/google.golang.org/grpc/internal/transport/handler_server.go
index 05d3871e628d074a5a80324f70fa92406ed7a14c..1c3459c2b4c5840f45404b1a7e77ddd1029f8e5a 100644
--- a/vendor/google.golang.org/grpc/internal/transport/handler_server.go
+++ b/vendor/google.golang.org/grpc/internal/transport/handler_server.go
@@ -141,9 +141,8 @@ type serverHandlerTransport struct {
 	stats stats.Handler
 }
 
-func (ht *serverHandlerTransport) Close() error {
+func (ht *serverHandlerTransport) Close() {
 	ht.closeOnce.Do(ht.closeCloseChanOnce)
-	return nil
 }
 
 func (ht *serverHandlerTransport) closeCloseChanOnce() { close(ht.closedCh) }
diff --git a/vendor/google.golang.org/grpc/internal/transport/http2_client.go b/vendor/google.golang.org/grpc/internal/transport/http2_client.go
index 48c5e52edae9b584131f6bcdaa7b8d36d24320e6..d10b6aacbcfed3b535ffb848eca5e817f0c91957 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http2_client.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http2_client.go
@@ -399,11 +399,10 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 				logger.Errorf("transport: loopyWriter.run returning. Err: %v", err)
 			}
 		}
-		// If it's a connection error, let reader goroutine handle it
-		// since there might be data in the buffers.
-		if _, ok := err.(net.Error); !ok {
-			t.conn.Close()
-		}
+		// Do not close the transport.  Let reader goroutine handle it since
+		// there might be data in the buffers.
+		t.conn.Close()
+		t.controlBuf.finish()
 		close(t.writerDone)
 	}()
 	return t, nil
@@ -878,12 +877,18 @@ func (t *http2Client) Close(err error) {
 	// Append info about previous goaways if there were any, since this may be important
 	// for understanding the root cause for this connection to be closed.
 	_, goAwayDebugMessage := t.GetGoAwayReason()
+
+	var st *status.Status
 	if len(goAwayDebugMessage) > 0 {
-		err = fmt.Errorf("closing transport due to: %v, received prior goaway: %v", err, goAwayDebugMessage)
+		st = status.Newf(codes.Unavailable, "closing transport due to: %v, received prior goaway: %v", err, goAwayDebugMessage)
+		err = st.Err()
+	} else {
+		st = status.New(codes.Unavailable, err.Error())
 	}
+
 	// Notify all active streams.
 	for _, s := range streams {
-		t.closeStream(s, err, false, http2.ErrCodeNo, status.New(codes.Unavailable, err.Error()), nil, false)
+		t.closeStream(s, err, false, http2.ErrCodeNo, st, nil, false)
 	}
 	if t.statsHandler != nil {
 		connEnd := &stats.ConnEnd{
@@ -1254,11 +1259,97 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 		return
 	}
 
-	state := &decodeState{}
-	// Initialize isGRPC value to be !initialHeader, since if a gRPC Response-Headers has already been received, then it means that the peer is speaking gRPC and we are in gRPC mode.
-	state.data.isGRPC = !initialHeader
-	if h2code, err := state.decodeHeader(frame); err != nil {
-		t.closeStream(s, err, true, h2code, status.Convert(err), nil, endStream)
+	// frame.Truncated is set to true when framer detects that the current header
+	// list size hits MaxHeaderListSize limit.
+	if frame.Truncated {
+		se := status.New(codes.Internal, "peer header list size exceeded limit")
+		t.closeStream(s, se.Err(), true, http2.ErrCodeFrameSize, se, nil, endStream)
+		return
+	}
+
+	var (
+		// If a gRPC Response-Headers has already been received, then it means
+		// that the peer is speaking gRPC and we are in gRPC mode.
+		isGRPC         = !initialHeader
+		mdata          = make(map[string][]string)
+		contentTypeErr string
+		grpcMessage    string
+		statusGen      *status.Status
+
+		httpStatus string
+		rawStatus  string
+		// headerError is set if an error is encountered while parsing the headers
+		headerError string
+	)
+
+	for _, hf := range frame.Fields {
+		switch hf.Name {
+		case "content-type":
+			if _, validContentType := grpcutil.ContentSubtype(hf.Value); !validContentType {
+				contentTypeErr = fmt.Sprintf("transport: received the unexpected content-type %q", hf.Value)
+				break
+			}
+			mdata[hf.Name] = append(mdata[hf.Name], hf.Value)
+			isGRPC = true
+		case "grpc-encoding":
+			s.recvCompress = hf.Value
+		case "grpc-status":
+			rawStatus = hf.Value
+		case "grpc-message":
+			grpcMessage = decodeGrpcMessage(hf.Value)
+		case "grpc-status-details-bin":
+			var err error
+			statusGen, err = decodeGRPCStatusDetails(hf.Value)
+			if err != nil {
+				headerError = fmt.Sprintf("transport: malformed grpc-status-details-bin: %v", err)
+			}
+		case ":status":
+			httpStatus = hf.Value
+		default:
+			if isReservedHeader(hf.Name) && !isWhitelistedHeader(hf.Name) {
+				break
+			}
+			v, err := decodeMetadataHeader(hf.Name, hf.Value)
+			if err != nil {
+				headerError = fmt.Sprintf("transport: malformed %s: %v", hf.Name, err)
+				logger.Warningf("Failed to decode metadata header (%q, %q): %v", hf.Name, hf.Value, err)
+				break
+			}
+			mdata[hf.Name] = append(mdata[hf.Name], v)
+		}
+	}
+
+	if !isGRPC {
+		var (
+			code           = codes.Internal // when header does not include HTTP status, return INTERNAL
+			httpStatusCode int
+		)
+
+		if httpStatus != "" {
+			c, err := strconv.ParseInt(httpStatus, 10, 32)
+			if err != nil {
+				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed http-status: %v", err))
+				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
+				return
+			}
+			httpStatusCode = int(c)
+
+			var ok bool
+			code, ok = HTTPStatusConvTab[httpStatusCode]
+			if !ok {
+				code = codes.Unknown
+			}
+		}
+
+		// Verify the HTTP response is a 200.
+		se := status.New(code, constructHTTPErrMsg(&httpStatusCode, contentTypeErr))
+		t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
+		return
+	}
+
+	if headerError != "" {
+		se := status.New(codes.Internal, headerError)
+		t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
 		return
 	}
 
@@ -1293,9 +1384,8 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 			// These values can be set without any synchronization because
 			// stream goroutine will read it only after seeing a closed
 			// headerChan which we'll close after setting this.
-			s.recvCompress = state.data.encoding
-			if len(state.data.mdata) > 0 {
-				s.header = state.data.mdata
+			if len(mdata) > 0 {
+				s.header = mdata
 			}
 		} else {
 			// HEADERS frame block carries a Trailers-Only.
@@ -1308,9 +1398,23 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 		return
 	}
 
+	if statusGen == nil {
+		rawStatusCode := codes.Unknown
+		if rawStatus != "" {
+			code, err := strconv.ParseInt(rawStatus, 10, 32)
+			if err != nil {
+				se := status.New(codes.Internal, fmt.Sprintf("transport: malformed grpc-status: %v", err))
+				t.closeStream(s, se.Err(), true, http2.ErrCodeProtocol, se, nil, endStream)
+				return
+			}
+			rawStatusCode = codes.Code(uint32(code))
+		}
+		statusGen = status.New(rawStatusCode, grpcMessage)
+	}
+
 	// if client received END_STREAM from server while stream was still active, send RST_STREAM
 	rst := s.getState() == streamActive
-	t.closeStream(s, io.EOF, rst, http2.ErrCodeNo, state.status(), state.data.mdata, true)
+	t.closeStream(s, io.EOF, rst, http2.ErrCodeNo, statusGen, mdata, true)
 }
 
 // reader runs as a separate goroutine in charge of reading data from network
diff --git a/vendor/google.golang.org/grpc/internal/transport/http2_server.go b/vendor/google.golang.org/grpc/internal/transport/http2_server.go
index 11be5599cd474c230cc2a43b754a4885ac74f670..e3799d50aa7127b74cd72a79d3eca0a9ed43e0dc 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http2_server.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http2_server.go
@@ -102,11 +102,11 @@ type http2Server struct {
 
 	mu sync.Mutex // guard the following
 
-	// drainChan is initialized when drain(...) is called the first time.
+	// drainChan is initialized when Drain() is called the first time.
 	// After which the server writes out the first GoAway(with ID 2^31-1) frame.
 	// Then an independent goroutine will be launched to later send the second GoAway.
 	// During this time we don't want to write another first GoAway(with ID 2^31 -1) frame.
-	// Thus call to drain(...) will be a no-op if drainChan is already initialized since draining is
+	// Thus call to Drain() will be a no-op if drainChan is already initialized since draining is
 	// already underway.
 	drainChan     chan struct{}
 	state         transportState
@@ -125,9 +125,14 @@ type http2Server struct {
 	connectionID uint64
 }
 
-// newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
-// returned if something goes wrong.
-func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
+// NewServerTransport creates a http2 transport with conn and configuration
+// options from config.
+//
+// It returns a non-nil transport and a nil error on success. On failure, it
+// returns a non-nil transport and a nil-error. For a special case where the
+// underlying conn gets closed before the client preface could be read, it
+// returns a nil transport and a nil error.
+func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
 	writeBufSize := config.WriteBufferSize
 	readBufSize := config.ReadBufferSize
 	maxHeaderListSize := defaultServerMaxHeaderListSize
@@ -266,6 +271,13 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 	// Check the validity of client preface.
 	preface := make([]byte, len(clientPreface))
 	if _, err := io.ReadFull(t.conn, preface); err != nil {
+		// In deployments where a gRPC server runs behind a cloud load balancer
+		// which performs regular TCP level health checks, the connection is
+		// closed immediately by the latter. Skipping the error here will help
+		// reduce log clutter.
+		if err == io.EOF {
+			return nil, nil
+		}
 		return nil, connectionErrorf(false, err, "transport: http2Server.HandleStreams failed to receive the preface from client: %v", err)
 	}
 	if !bytes.Equal(preface, clientPreface) {
@@ -295,6 +307,7 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 			}
 		}
 		t.conn.Close()
+		t.controlBuf.finish()
 		close(t.writerDone)
 	}()
 	go t.keepalive()
@@ -304,37 +317,92 @@ func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err
 // operateHeader takes action on the decoded headers.
 func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (fatal bool) {
 	streamID := frame.Header().StreamID
-	state := &decodeState{
-		serverSide: true,
-	}
-	if h2code, err := state.decodeHeader(frame); err != nil {
-		if _, ok := status.FromError(err); ok {
-			t.controlBuf.put(&cleanupStream{
-				streamID: streamID,
-				rst:      true,
-				rstCode:  h2code,
-				onWrite:  func() {},
-			})
-		}
+
+	// frame.Truncated is set to true when framer detects that the current header
+	// list size hits MaxHeaderListSize limit.
+	if frame.Truncated {
+		t.controlBuf.put(&cleanupStream{
+			streamID: streamID,
+			rst:      true,
+			rstCode:  http2.ErrCodeFrameSize,
+			onWrite:  func() {},
+		})
 		return false
 	}
 
 	buf := newRecvBuffer()
 	s := &Stream{
-		id:             streamID,
-		st:             t,
-		buf:            buf,
-		fc:             &inFlow{limit: uint32(t.initialWindowSize)},
-		recvCompress:   state.data.encoding,
-		method:         state.data.method,
-		contentSubtype: state.data.contentSubtype,
+		id:  streamID,
+		st:  t,
+		buf: buf,
+		fc:  &inFlow{limit: uint32(t.initialWindowSize)},
+	}
+
+	var (
+		// If a gRPC Response-Headers has already been received, then it means
+		// that the peer is speaking gRPC and we are in gRPC mode.
+		isGRPC     = false
+		mdata      = make(map[string][]string)
+		httpMethod string
+		// headerError is set if an error is encountered while parsing the headers
+		headerError bool
+
+		timeoutSet bool
+		timeout    time.Duration
+	)
+
+	for _, hf := range frame.Fields {
+		switch hf.Name {
+		case "content-type":
+			contentSubtype, validContentType := grpcutil.ContentSubtype(hf.Value)
+			if !validContentType {
+				break
+			}
+			mdata[hf.Name] = append(mdata[hf.Name], hf.Value)
+			s.contentSubtype = contentSubtype
+			isGRPC = true
+		case "grpc-encoding":
+			s.recvCompress = hf.Value
+		case ":method":
+			httpMethod = hf.Value
+		case ":path":
+			s.method = hf.Value
+		case "grpc-timeout":
+			timeoutSet = true
+			var err error
+			if timeout, err = decodeTimeout(hf.Value); err != nil {
+				headerError = true
+			}
+		default:
+			if isReservedHeader(hf.Name) && !isWhitelistedHeader(hf.Name) {
+				break
+			}
+			v, err := decodeMetadataHeader(hf.Name, hf.Value)
+			if err != nil {
+				headerError = true
+				logger.Warningf("Failed to decode metadata header (%q, %q): %v", hf.Name, hf.Value, err)
+				break
+			}
+			mdata[hf.Name] = append(mdata[hf.Name], v)
+		}
 	}
+
+	if !isGRPC || headerError {
+		t.controlBuf.put(&cleanupStream{
+			streamID: streamID,
+			rst:      true,
+			rstCode:  http2.ErrCodeProtocol,
+			onWrite:  func() {},
+		})
+		return false
+	}
+
 	if frame.StreamEnded() {
 		// s is just created by the caller. No lock needed.
 		s.state = streamReadDone
 	}
-	if state.data.timeoutSet {
-		s.ctx, s.cancel = context.WithTimeout(t.ctx, state.data.timeout)
+	if timeoutSet {
+		s.ctx, s.cancel = context.WithTimeout(t.ctx, timeout)
 	} else {
 		s.ctx, s.cancel = context.WithCancel(t.ctx)
 	}
@@ -347,14 +415,14 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	s.ctx = peer.NewContext(s.ctx, pr)
 	// Attach the received metadata to the context.
-	if len(state.data.mdata) > 0 {
-		s.ctx = metadata.NewIncomingContext(s.ctx, state.data.mdata)
-	}
-	if state.data.statsTags != nil {
-		s.ctx = stats.SetIncomingTags(s.ctx, state.data.statsTags)
-	}
-	if state.data.statsTrace != nil {
-		s.ctx = stats.SetIncomingTrace(s.ctx, state.data.statsTrace)
+	if len(mdata) > 0 {
+		s.ctx = metadata.NewIncomingContext(s.ctx, mdata)
+		if statsTags := mdata["grpc-tags-bin"]; len(statsTags) > 0 {
+			s.ctx = stats.SetIncomingTags(s.ctx, []byte(statsTags[len(statsTags)-1]))
+		}
+		if statsTrace := mdata["grpc-trace-bin"]; len(statsTrace) > 0 {
+			s.ctx = stats.SetIncomingTrace(s.ctx, []byte(statsTrace[len(statsTrace)-1]))
+		}
 	}
 	t.mu.Lock()
 	if t.state != reachable {
@@ -383,10 +451,10 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 		return true
 	}
 	t.maxStreamID = streamID
-	if state.data.httpMethod != http.MethodPost {
+	if httpMethod != http.MethodPost {
 		t.mu.Unlock()
 		if logger.V(logLevel) {
-			logger.Warningf("transport: http2Server.operateHeaders parsed a :method field: %v which should be POST", state.data.httpMethod)
+			logger.Infof("transport: http2Server.operateHeaders parsed a :method field: %v which should be POST", httpMethod)
 		}
 		t.controlBuf.put(&cleanupStream{
 			streamID: streamID,
@@ -399,7 +467,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	if t.inTapHandle != nil {
 		var err error
-		if s.ctx, err = t.inTapHandle(s.ctx, &tap.Info{FullMethodName: state.data.method}); err != nil {
+		if s.ctx, err = t.inTapHandle(s.ctx, &tap.Info{FullMethodName: s.method}); err != nil {
 			t.mu.Unlock()
 			if logger.V(logLevel) {
 				logger.Infof("transport: http2Server.operateHeaders got an error from InTapHandle: %v", err)
@@ -437,7 +505,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 			LocalAddr:   t.localAddr,
 			Compression: s.recvCompress,
 			WireLength:  int(frame.Header().Length),
-			Header:      metadata.MD(state.data.mdata).Copy(),
+			Header:      metadata.MD(mdata).Copy(),
 		}
 		t.stats.HandleRPC(s.ctx, inHeader)
 	}
@@ -1004,12 +1072,12 @@ func (t *http2Server) keepalive() {
 			if val <= 0 {
 				// The connection has been idle for a duration of keepalive.MaxConnectionIdle or more.
 				// Gracefully close the connection.
-				t.drain(http2.ErrCodeNo, []byte{})
+				t.Drain()
 				return
 			}
 			idleTimer.Reset(val)
 		case <-ageTimer.C:
-			t.drain(http2.ErrCodeNo, []byte{})
+			t.Drain()
 			ageTimer.Reset(t.kp.MaxConnectionAgeGrace)
 			select {
 			case <-ageTimer.C:
@@ -1063,11 +1131,11 @@ func (t *http2Server) keepalive() {
 // Close starts shutting down the http2Server transport.
 // TODO(zhaoq): Now the destruction is not blocked on any pending streams. This
 // could cause some resource issue. Revisit this later.
-func (t *http2Server) Close() error {
+func (t *http2Server) Close() {
 	t.mu.Lock()
 	if t.state == closing {
 		t.mu.Unlock()
-		return errors.New("transport: Close() was already called")
+		return
 	}
 	t.state = closing
 	streams := t.activeStreams
@@ -1075,7 +1143,9 @@ func (t *http2Server) Close() error {
 	t.mu.Unlock()
 	t.controlBuf.finish()
 	close(t.done)
-	err := t.conn.Close()
+	if err := t.conn.Close(); err != nil && logger.V(logLevel) {
+		logger.Infof("transport: error closing conn during Close: %v", err)
+	}
 	if channelz.IsOn() {
 		channelz.RemoveEntry(t.channelzID)
 	}
@@ -1087,7 +1157,6 @@ func (t *http2Server) Close() error {
 		connEnd := &stats.ConnEnd{}
 		t.stats.HandleConn(t.ctx, connEnd)
 	}
-	return err
 }
 
 // deleteStream deletes the stream s from transport's active streams.
@@ -1152,17 +1221,13 @@ func (t *http2Server) RemoteAddr() net.Addr {
 }
 
 func (t *http2Server) Drain() {
-	t.drain(http2.ErrCodeNo, []byte{})
-}
-
-func (t *http2Server) drain(code http2.ErrCode, debugData []byte) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 	if t.drainChan != nil {
 		return
 	}
 	t.drainChan = make(chan struct{})
-	t.controlBuf.put(&goAway{code: code, debugData: debugData, headsUp: true})
+	t.controlBuf.put(&goAway{code: http2.ErrCodeNo, debugData: []byte{}, headsUp: true})
 }
 
 var goAwayPing = &ping{data: [8]byte{1, 6, 1, 8, 0, 3, 3, 9}}
diff --git a/vendor/google.golang.org/grpc/internal/transport/http_util.go b/vendor/google.golang.org/grpc/internal/transport/http_util.go
index c7dee140cf1a2bde5785328d28af82c8fea5e296..15d775fca3ccda8ba06a8a1a011f61a08c15f46b 100644
--- a/vendor/google.golang.org/grpc/internal/transport/http_util.go
+++ b/vendor/google.golang.org/grpc/internal/transport/http_util.go
@@ -39,7 +39,6 @@ import (
 	spb "google.golang.org/genproto/googleapis/rpc/status"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/grpclog"
-	"google.golang.org/grpc/internal/grpcutil"
 	"google.golang.org/grpc/status"
 )
 
@@ -96,53 +95,6 @@ var (
 	logger = grpclog.Component("transport")
 )
 
-type parsedHeaderData struct {
-	encoding string
-	// statusGen caches the stream status received from the trailer the server
-	// sent.  Client side only.  Do not access directly.  After all trailers are
-	// parsed, use the status method to retrieve the status.
-	statusGen *status.Status
-	// rawStatusCode and rawStatusMsg are set from the raw trailer fields and are not
-	// intended for direct access outside of parsing.
-	rawStatusCode *int
-	rawStatusMsg  string
-	httpStatus    *int
-	// Server side only fields.
-	timeoutSet bool
-	timeout    time.Duration
-	method     string
-	httpMethod string
-	// key-value metadata map from the peer.
-	mdata          map[string][]string
-	statsTags      []byte
-	statsTrace     []byte
-	contentSubtype string
-
-	// isGRPC field indicates whether the peer is speaking gRPC (otherwise HTTP).
-	//
-	// We are in gRPC mode (peer speaking gRPC) if:
-	// 	* We are client side and have already received a HEADER frame that indicates gRPC peer.
-	//  * The header contains valid  a content-type, i.e. a string starts with "application/grpc"
-	// And we should handle error specific to gRPC.
-	//
-	// Otherwise (i.e. a content-type string starts without "application/grpc", or does not exist), we
-	// are in HTTP fallback mode, and should handle error specific to HTTP.
-	isGRPC         bool
-	grpcErr        error
-	httpErr        error
-	contentTypeErr string
-}
-
-// decodeState configures decoding criteria and records the decoded data.
-type decodeState struct {
-	// whether decoding on server side or not
-	serverSide bool
-
-	// Records the states during HPACK decoding. It will be filled with info parsed from HTTP HEADERS
-	// frame once decodeHeader function has been invoked and returned.
-	data parsedHeaderData
-}
-
 // isReservedHeader checks whether hdr belongs to HTTP2 headers
 // reserved by gRPC protocol. Any other headers are classified as the
 // user-specified metadata.
@@ -180,14 +132,6 @@ func isWhitelistedHeader(hdr string) bool {
 	}
 }
 
-func (d *decodeState) status() *status.Status {
-	if d.data.statusGen == nil {
-		// No status-details were provided; generate status using code/msg.
-		d.data.statusGen = status.New(codes.Code(int32(*(d.data.rawStatusCode))), d.data.rawStatusMsg)
-	}
-	return d.data.statusGen
-}
-
 const binHdrSuffix = "-bin"
 
 func encodeBinHeader(v []byte) string {
@@ -217,170 +161,38 @@ func decodeMetadataHeader(k, v string) (string, error) {
 	return v, nil
 }
 
-func (d *decodeState) decodeHeader(frame *http2.MetaHeadersFrame) (http2.ErrCode, error) {
-	// frame.Truncated is set to true when framer detects that the current header
-	// list size hits MaxHeaderListSize limit.
-	if frame.Truncated {
-		return http2.ErrCodeFrameSize, status.Error(codes.Internal, "peer header list size exceeded limit")
-	}
-
-	for _, hf := range frame.Fields {
-		d.processHeaderField(hf)
-	}
-
-	if d.data.isGRPC {
-		if d.data.grpcErr != nil {
-			return http2.ErrCodeProtocol, d.data.grpcErr
-		}
-		if d.serverSide {
-			return http2.ErrCodeNo, nil
-		}
-		if d.data.rawStatusCode == nil && d.data.statusGen == nil {
-			// gRPC status doesn't exist.
-			// Set rawStatusCode to be unknown and return nil error.
-			// So that, if the stream has ended this Unknown status
-			// will be propagated to the user.
-			// Otherwise, it will be ignored. In which case, status from
-			// a later trailer, that has StreamEnded flag set, is propagated.
-			code := int(codes.Unknown)
-			d.data.rawStatusCode = &code
-		}
-		return http2.ErrCodeNo, nil
+func decodeGRPCStatusDetails(rawDetails string) (*status.Status, error) {
+	v, err := decodeBinHeader(rawDetails)
+	if err != nil {
+		return nil, err
 	}
-
-	// HTTP fallback mode
-	if d.data.httpErr != nil {
-		return http2.ErrCodeProtocol, d.data.httpErr
+	st := &spb.Status{}
+	if err = proto.Unmarshal(v, st); err != nil {
+		return nil, err
 	}
-
-	var (
-		code = codes.Internal // when header does not include HTTP status, return INTERNAL
-		ok   bool
-	)
-
-	if d.data.httpStatus != nil {
-		code, ok = HTTPStatusConvTab[*(d.data.httpStatus)]
-		if !ok {
-			code = codes.Unknown
-		}
-	}
-
-	return http2.ErrCodeProtocol, status.Error(code, d.constructHTTPErrMsg())
+	return status.FromProto(st), nil
 }
 
 // constructErrMsg constructs error message to be returned in HTTP fallback mode.
 // Format: HTTP status code and its corresponding message + content-type error message.
-func (d *decodeState) constructHTTPErrMsg() string {
+func constructHTTPErrMsg(httpStatus *int, contentTypeErr string) string {
 	var errMsgs []string
 
-	if d.data.httpStatus == nil {
+	if httpStatus == nil {
 		errMsgs = append(errMsgs, "malformed header: missing HTTP status")
 	} else {
-		errMsgs = append(errMsgs, fmt.Sprintf("%s: HTTP status code %d", http.StatusText(*(d.data.httpStatus)), *d.data.httpStatus))
+		errMsgs = append(errMsgs, fmt.Sprintf("%s: HTTP status code %d", http.StatusText(*(httpStatus)), *httpStatus))
 	}
 
-	if d.data.contentTypeErr == "" {
+	if contentTypeErr == "" {
 		errMsgs = append(errMsgs, "transport: missing content-type field")
 	} else {
-		errMsgs = append(errMsgs, d.data.contentTypeErr)
+		errMsgs = append(errMsgs, contentTypeErr)
 	}
 
 	return strings.Join(errMsgs, "; ")
 }
 
-func (d *decodeState) addMetadata(k, v string) {
-	if d.data.mdata == nil {
-		d.data.mdata = make(map[string][]string)
-	}
-	d.data.mdata[k] = append(d.data.mdata[k], v)
-}
-
-func (d *decodeState) processHeaderField(f hpack.HeaderField) {
-	switch f.Name {
-	case "content-type":
-		contentSubtype, validContentType := grpcutil.ContentSubtype(f.Value)
-		if !validContentType {
-			d.data.contentTypeErr = fmt.Sprintf("transport: received the unexpected content-type %q", f.Value)
-			return
-		}
-		d.data.contentSubtype = contentSubtype
-		// TODO: do we want to propagate the whole content-type in the metadata,
-		// or come up with a way to just propagate the content-subtype if it was set?
-		// ie {"content-type": "application/grpc+proto"} or {"content-subtype": "proto"}
-		// in the metadata?
-		d.addMetadata(f.Name, f.Value)
-		d.data.isGRPC = true
-	case "grpc-encoding":
-		d.data.encoding = f.Value
-	case "grpc-status":
-		code, err := strconv.Atoi(f.Value)
-		if err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status: %v", err)
-			return
-		}
-		d.data.rawStatusCode = &code
-	case "grpc-message":
-		d.data.rawStatusMsg = decodeGrpcMessage(f.Value)
-	case "grpc-status-details-bin":
-		v, err := decodeBinHeader(f.Value)
-		if err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
-			return
-		}
-		s := &spb.Status{}
-		if err := proto.Unmarshal(v, s); err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-status-details-bin: %v", err)
-			return
-		}
-		d.data.statusGen = status.FromProto(s)
-	case "grpc-timeout":
-		d.data.timeoutSet = true
-		var err error
-		if d.data.timeout, err = decodeTimeout(f.Value); err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed time-out: %v", err)
-		}
-	case ":path":
-		d.data.method = f.Value
-	case ":status":
-		code, err := strconv.Atoi(f.Value)
-		if err != nil {
-			d.data.httpErr = status.Errorf(codes.Internal, "transport: malformed http-status: %v", err)
-			return
-		}
-		d.data.httpStatus = &code
-	case "grpc-tags-bin":
-		v, err := decodeBinHeader(f.Value)
-		if err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-tags-bin: %v", err)
-			return
-		}
-		d.data.statsTags = v
-		d.addMetadata(f.Name, string(v))
-	case "grpc-trace-bin":
-		v, err := decodeBinHeader(f.Value)
-		if err != nil {
-			d.data.grpcErr = status.Errorf(codes.Internal, "transport: malformed grpc-trace-bin: %v", err)
-			return
-		}
-		d.data.statsTrace = v
-		d.addMetadata(f.Name, string(v))
-	case ":method":
-		d.data.httpMethod = f.Value
-	default:
-		if isReservedHeader(f.Name) && !isWhitelistedHeader(f.Name) {
-			break
-		}
-		v, err := decodeMetadataHeader(f.Name, f.Value)
-		if err != nil {
-			if logger.V(logLevel) {
-				logger.Errorf("Failed to decode metadata header (%q, %q): %v", f.Name, f.Value, err)
-			}
-			return
-		}
-		d.addMetadata(f.Name, v)
-	}
-}
-
 type timeoutUnit uint8
 
 const (
diff --git a/vendor/google.golang.org/grpc/internal/transport/networktype/networktype.go b/vendor/google.golang.org/grpc/internal/transport/networktype/networktype.go
index 96967428b51513f31b1775e53ee2bf7cfb8fd84b..7bb53cff1011140a683026989e662e37ca432ec0 100644
--- a/vendor/google.golang.org/grpc/internal/transport/networktype/networktype.go
+++ b/vendor/google.golang.org/grpc/internal/transport/networktype/networktype.go
@@ -17,7 +17,7 @@
  */
 
 // Package networktype declares the network type to be used in the default
-// dailer. Attribute of a resolver.Address.
+// dialer. Attribute of a resolver.Address.
 package networktype
 
 import (
diff --git a/vendor/google.golang.org/grpc/internal/transport/transport.go b/vendor/google.golang.org/grpc/internal/transport/transport.go
index 6cc1031fd92f8fdf3963cf2961427d84a4faeb84..14198126457b988d38bcab99a66017f30320e670 100644
--- a/vendor/google.golang.org/grpc/internal/transport/transport.go
+++ b/vendor/google.golang.org/grpc/internal/transport/transport.go
@@ -532,12 +532,6 @@ type ServerConfig struct {
 	HeaderTableSize       *uint32
 }
 
-// NewServerTransport creates a ServerTransport with conn or non-nil error
-// if it fails.
-func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) {
-	return newHTTP2Server(conn, config)
-}
-
 // ConnectOptions covers all relevant options for communicating with the server.
 type ConnectOptions struct {
 	// UserAgent is the application user agent.
@@ -694,7 +688,7 @@ type ServerTransport interface {
 	// Close tears down the transport. Once it is called, the transport
 	// should not be accessed any more. All the pending streams and their
 	// handlers will be terminated asynchronously.
-	Close() error
+	Close()
 
 	// RemoteAddr returns the remote network address.
 	RemoteAddr() net.Addr
diff --git a/vendor/google.golang.org/grpc/metadata/metadata.go b/vendor/google.golang.org/grpc/metadata/metadata.go
index e4cbea9174983e7e5cd9959c82bbb947d7e56661..8d9686375a136e62239771fdd0a1ef42d068420f 100644
--- a/vendor/google.golang.org/grpc/metadata/metadata.go
+++ b/vendor/google.golang.org/grpc/metadata/metadata.go
@@ -93,12 +93,16 @@ func (md MD) Copy() MD {
 }
 
 // Get obtains the values for a given key.
+//
+// k is converted to lowercase before searching in md.
 func (md MD) Get(k string) []string {
 	k = strings.ToLower(k)
 	return md[k]
 }
 
 // Set sets the value of a given key with a slice of values.
+//
+// k is converted to lowercase before storing in md.
 func (md MD) Set(k string, vals ...string) {
 	if len(vals) == 0 {
 		return
@@ -107,7 +111,10 @@ func (md MD) Set(k string, vals ...string) {
 	md[k] = vals
 }
 
-// Append adds the values to key k, not overwriting what was already stored at that key.
+// Append adds the values to key k, not overwriting what was already stored at
+// that key.
+//
+// k is converted to lowercase before storing in md.
 func (md MD) Append(k string, vals ...string) {
 	if len(vals) == 0 {
 		return
@@ -117,8 +124,9 @@ func (md MD) Append(k string, vals ...string) {
 }
 
 // Join joins any number of mds into a single MD.
-// The order of values for each key is determined by the order in which
-// the mds containing those values are presented to Join.
+//
+// The order of values for each key is determined by the order in which the mds
+// containing those values are presented to Join.
 func Join(mds ...MD) MD {
 	out := MD{}
 	for _, md := range mds {
@@ -145,8 +153,8 @@ func NewOutgoingContext(ctx context.Context, md MD) context.Context {
 }
 
 // AppendToOutgoingContext returns a new context with the provided kv merged
-// with any existing metadata in the context. Please refer to the
-// documentation of Pairs for a description of kv.
+// with any existing metadata in the context. Please refer to the documentation
+// of Pairs for a description of kv.
 func AppendToOutgoingContext(ctx context.Context, kv ...string) context.Context {
 	if len(kv)%2 == 1 {
 		panic(fmt.Sprintf("metadata: AppendToOutgoingContext got an odd number of input pairs for metadata: %d", len(kv)))
@@ -159,20 +167,34 @@ func AppendToOutgoingContext(ctx context.Context, kv ...string) context.Context
 	return context.WithValue(ctx, mdOutgoingKey{}, rawMD{md: md.md, added: added})
 }
 
-// FromIncomingContext returns the incoming metadata in ctx if it exists.  The
-// returned MD should not be modified. Writing to it may cause races.
-// Modification should be made to copies of the returned MD.
-func FromIncomingContext(ctx context.Context) (md MD, ok bool) {
-	md, ok = ctx.Value(mdIncomingKey{}).(MD)
-	return
+// FromIncomingContext returns the incoming metadata in ctx if it exists.
+//
+// All keys in the returned MD are lowercase.
+func FromIncomingContext(ctx context.Context) (MD, bool) {
+	md, ok := ctx.Value(mdIncomingKey{}).(MD)
+	if !ok {
+		return nil, false
+	}
+	out := MD{}
+	for k, v := range md {
+		// We need to manually convert all keys to lower case, because MD is a
+		// map, and there's no guarantee that the MD attached to the context is
+		// created using our helper functions.
+		key := strings.ToLower(k)
+		out[key] = v
+	}
+	return out, true
 }
 
-// FromOutgoingContextRaw returns the un-merged, intermediary contents
-// of rawMD. Remember to perform strings.ToLower on the keys. The returned
-// MD should not be modified. Writing to it may cause races. Modification
-// should be made to copies of the returned MD.
+// FromOutgoingContextRaw returns the un-merged, intermediary contents of rawMD.
+//
+// Remember to perform strings.ToLower on the keys, for both the returned MD (MD
+// is a map, there's no guarantee it's created using our helper functions) and
+// the extra kv pairs (AppendToOutgoingContext doesn't turn them into
+// lowercase).
 //
-// This is intended for gRPC-internal use ONLY.
+// This is intended for gRPC-internal use ONLY. Users should use
+// FromOutgoingContext instead.
 func FromOutgoingContextRaw(ctx context.Context) (MD, [][]string, bool) {
 	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
 	if !ok {
@@ -182,16 +204,23 @@ func FromOutgoingContextRaw(ctx context.Context) (MD, [][]string, bool) {
 	return raw.md, raw.added, true
 }
 
-// FromOutgoingContext returns the outgoing metadata in ctx if it exists.  The
-// returned MD should not be modified. Writing to it may cause races.
-// Modification should be made to copies of the returned MD.
+// FromOutgoingContext returns the outgoing metadata in ctx if it exists.
+//
+// All keys in the returned MD are lowercase.
 func FromOutgoingContext(ctx context.Context) (MD, bool) {
 	raw, ok := ctx.Value(mdOutgoingKey{}).(rawMD)
 	if !ok {
 		return nil, false
 	}
 
-	out := raw.md.Copy()
+	out := MD{}
+	for k, v := range raw.md {
+		// We need to manually convert all keys to lower case, because MD is a
+		// map, and there's no guarantee that the MD attached to the context is
+		// created using our helper functions.
+		key := strings.ToLower(k)
+		out[key] = v
+	}
 	for _, added := range raw.added {
 		if len(added)%2 == 1 {
 			panic(fmt.Sprintf("metadata: FromOutgoingContext got an odd number of input pairs for metadata: %d", len(added)))
diff --git a/vendor/google.golang.org/grpc/resolver_conn_wrapper.go b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
index 4118de571ab5bcfae6d79f431d0d239d78931220..2c47cd54f07c9934778f94784e4ac33a5fd20270 100644
--- a/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
+++ b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
@@ -39,6 +39,8 @@ type ccResolverWrapper struct {
 	resolver   resolver.Resolver
 	done       *grpcsync.Event
 	curState   resolver.State
+
+	incomingMu sync.Mutex // Synchronizes all the incoming calls.
 }
 
 // newCCResolverWrapper uses the resolver.Builder to build a Resolver and
@@ -90,6 +92,8 @@ func (ccr *ccResolverWrapper) close() {
 }
 
 func (ccr *ccResolverWrapper) UpdateState(s resolver.State) error {
+	ccr.incomingMu.Lock()
+	defer ccr.incomingMu.Unlock()
 	if ccr.done.HasFired() {
 		return nil
 	}
@@ -105,6 +109,8 @@ func (ccr *ccResolverWrapper) UpdateState(s resolver.State) error {
 }
 
 func (ccr *ccResolverWrapper) ReportError(err error) {
+	ccr.incomingMu.Lock()
+	defer ccr.incomingMu.Unlock()
 	if ccr.done.HasFired() {
 		return
 	}
@@ -114,6 +120,8 @@ func (ccr *ccResolverWrapper) ReportError(err error) {
 
 // NewAddress is called by the resolver implementation to send addresses to gRPC.
 func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	ccr.incomingMu.Lock()
+	defer ccr.incomingMu.Unlock()
 	if ccr.done.HasFired() {
 		return
 	}
@@ -128,6 +136,8 @@ func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
 // NewServiceConfig is called by the resolver implementation to send service
 // configs to gRPC.
 func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
+	ccr.incomingMu.Lock()
+	defer ccr.incomingMu.Unlock()
 	if ccr.done.HasFired() {
 		return
 	}
diff --git a/vendor/google.golang.org/grpc/rpc_util.go b/vendor/google.golang.org/grpc/rpc_util.go
index 6db356fa56a7993bdcdcb0b07934397e37e0b76b..1831a73e73d37d0311532f40d6191b4d8049ad13 100644
--- a/vendor/google.golang.org/grpc/rpc_util.go
+++ b/vendor/google.golang.org/grpc/rpc_util.go
@@ -258,7 +258,8 @@ func (o PeerCallOption) after(c *callInfo, attempt *csAttempt) {
 }
 
 // WaitForReady configures the action to take when an RPC is attempted on broken
-// connections or unreachable servers. If waitForReady is false, the RPC will fail
+// connections or unreachable servers. If waitForReady is false and the
+// connection is in the TRANSIENT_FAILURE state, the RPC will fail
 // immediately. Otherwise, the RPC client will block the call until a
 // connection is available (or the call is canceled or times out) and will
 // retry the call if it fails due to a transient error.  gRPC will not retry if
diff --git a/vendor/google.golang.org/grpc/server.go b/vendor/google.golang.org/grpc/server.go
index 0a151dee4fcba24a9720868caf42a1e12dc3dc19..d90f3fcd3bf6f36d2e18898aac01885bb9af7900 100644
--- a/vendor/google.golang.org/grpc/server.go
+++ b/vendor/google.golang.org/grpc/server.go
@@ -844,10 +844,16 @@ func (s *Server) handleRawConn(lisAddr string, rawConn net.Conn) {
 		// ErrConnDispatched means that the connection was dispatched away from
 		// gRPC; those connections should be left open.
 		if err != credentials.ErrConnDispatched {
-			s.mu.Lock()
-			s.errorf("ServerHandshake(%q) failed: %v", rawConn.RemoteAddr(), err)
-			s.mu.Unlock()
-			channelz.Warningf(logger, s.channelzID, "grpc: Server.Serve failed to complete security handshake from %q: %v", rawConn.RemoteAddr(), err)
+			// In deployments where a gRPC server runs behind a cloud load
+			// balancer which performs regular TCP level health checks, the
+			// connection is closed immediately by the latter. Skipping the
+			// error here will help reduce log clutter.
+			if err != io.EOF {
+				s.mu.Lock()
+				s.errorf("ServerHandshake(%q) failed: %v", rawConn.RemoteAddr(), err)
+				s.mu.Unlock()
+				channelz.Warningf(logger, s.channelzID, "grpc: Server.Serve failed to complete security handshake from %q: %v", rawConn.RemoteAddr(), err)
+			}
 			rawConn.Close()
 		}
 		rawConn.SetDeadline(time.Time{})
@@ -897,7 +903,7 @@ func (s *Server) newHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) tr
 		MaxHeaderListSize:     s.opts.maxHeaderListSize,
 		HeaderTableSize:       s.opts.headerTableSize,
 	}
-	st, err := transport.NewServerTransport("http2", c, config)
+	st, err := transport.NewServerTransport(c, config)
 	if err != nil {
 		s.mu.Lock()
 		s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
@@ -1521,6 +1527,8 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 		}
 	}
 
+	ss.ctx = newContextWithRPCInfo(ss.ctx, false, ss.codec, ss.cp, ss.comp)
+
 	if trInfo != nil {
 		trInfo.tr.LazyLog(&trInfo.firstLine, false)
 	}
@@ -1588,7 +1596,7 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 			trInfo.tr.SetError()
 		}
 		errDesc := fmt.Sprintf("malformed method name: %q", stream.Method())
-		if err := t.WriteStatus(stream, status.New(codes.ResourceExhausted, errDesc)); err != nil {
+		if err := t.WriteStatus(stream, status.New(codes.Unimplemented, errDesc)); err != nil {
 			if trInfo != nil {
 				trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 				trInfo.tr.SetError()
diff --git a/vendor/google.golang.org/grpc/version.go b/vendor/google.golang.org/grpc/version.go
index bfe5cf88703d2f0b716e093f807a552ac6a71226..3dd146afb18d72a2e8f8c48bac5edb289b38bf9d 100644
--- a/vendor/google.golang.org/grpc/version.go
+++ b/vendor/google.golang.org/grpc/version.go
@@ -19,4 +19,4 @@
 package grpc
 
 // Version is the current grpc version.
-const Version = "1.38.0"
+const Version = "1.39.0"
diff --git a/vendor/google.golang.org/grpc/vet.sh b/vendor/google.golang.org/grpc/vet.sh
index 1a0dbd7ee5abcb93e88ecd7d73d70de9de2df321..5eaa8b05d6d39b67d6f0efe78740867ba2b1b6c2 100644
--- a/vendor/google.golang.org/grpc/vet.sh
+++ b/vendor/google.golang.org/grpc/vet.sh
@@ -32,26 +32,14 @@ PATH="${HOME}/go/bin:${GOROOT}/bin:${PATH}"
 go version
 
 if [[ "$1" = "-install" ]]; then
-  # Check for module support
-  if go help mod >& /dev/null; then
-    # Install the pinned versions as defined in module tools.
-    pushd ./test/tools
-    go install \
-      golang.org/x/lint/golint \
-      golang.org/x/tools/cmd/goimports \
-      honnef.co/go/tools/cmd/staticcheck \
-      github.com/client9/misspell/cmd/misspell
-    popd
-  else
-    # Ye olde `go get` incantation.
-    # Note: this gets the latest version of all tools (vs. the pinned versions
-    # with Go modules).
-    go get -u \
-      golang.org/x/lint/golint \
-      golang.org/x/tools/cmd/goimports \
-      honnef.co/go/tools/cmd/staticcheck \
-      github.com/client9/misspell/cmd/misspell
-  fi
+  # Install the pinned versions as defined in module tools.
+  pushd ./test/tools
+  go install \
+    golang.org/x/lint/golint \
+    golang.org/x/tools/cmd/goimports \
+    honnef.co/go/tools/cmd/staticcheck \
+    github.com/client9/misspell/cmd/misspell
+  popd
   if [[ -z "${VET_SKIP_PROTO}" ]]; then
     if [[ "${TRAVIS}" = "true" ]]; then
       PROTOBUF_VERSION=3.14.0
diff --git a/vendor/modules.txt b/vendor/modules.txt
index d27039d7f77a5b02dee3149f3b6296eb4bf15b5d..e95d7d11c1b2ecf4d92dd4fa0fa0185bdab5eb69 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -110,7 +110,7 @@ golang.org/x/text/unicode/norm
 # google.golang.org/genproto v0.0.0-20210416161957-9910b6c460de
 ## explicit
 google.golang.org/genproto/googleapis/rpc/status
-# google.golang.org/grpc v1.38.0
+# google.golang.org/grpc v1.39.0
 ## explicit
 google.golang.org/grpc
 google.golang.org/grpc/attributes