vendor/github.com/cenkalti/backoff/.gitignore → vendor/github.com/cenkalti/backoff/v4/.gitignore

@@ -20,3 +20,6 @@ _cgo_export.*
 _testmain.go
 
 *.exe
+
+# IDEs
+.idea/

vendor/github.com/cenkalti/backoff/.travis.yml → vendor/github.com/cenkalti/backoff/v4/.travis.yml

 language: go
 go:
-  - 1.7
+  - 1.13
   - 1.x
   - tip
 before_install:

vendor/github.com/cenkalti/backoff/README.md → vendor/github.com/cenkalti/backoff/v4/README.md

@@ -9,7 +9,9 @@ The retries exponentially increase and stop increasing when a certain threshold
 
 ## Usage
 
-See https://godoc.org/github.com/cenkalti/backoff#pkg-examples
+Import path is `github.com/cenkalti/backoff/v4`. Please note the version part at the end.
+
+Use https://pkg.go.dev/github.com/cenkalti/backoff/v4 to view the documentation.
 
 ## Contributing
 
@@ -17,7 +19,7 @@ See https://godoc.org/github.com/cenkalti/backoff#pkg-examples
 * Please don't send a PR without opening an issue and discussing it first.
 * If proposed change is not a common use case, I will probably not accept it.
 
-[godoc]: https://godoc.org/github.com/cenkalti/backoff
+[godoc]: https://pkg.go.dev/github.com/cenkalti/backoff/v4
 [godoc image]: https://godoc.org/github.com/cenkalti/backoff?status.png
 [travis]: https://travis-ci.org/cenkalti/backoff
 [travis image]: https://travis-ci.org/cenkalti/backoff.png?branch=master
@@ -27,4 +29,4 @@ See https://godoc.org/github.com/cenkalti/backoff#pkg-examples
 [google-http-java-client]: https://github.com/google/google-http-java-client/blob/da1aa993e90285ec18579f1553339b00e19b3ab5/google-http-client/src/main/java/com/google/api/client/util/ExponentialBackOff.java
 [exponential backoff wiki]: http://en.wikipedia.org/wiki/Exponential_backoff
 
-[advanced example]: https://godoc.org/github.com/cenkalti/backoff#example_
+[advanced example]: https://pkg.go.dev/github.com/cenkalti/backoff/v4?tab=doc#pkg-examples

vendor/github.com/cenkalti/backoff/context.go → vendor/github.com/cenkalti/backoff/v4/context.go

@@ -7,7 +7,7 @@ import (
 
 // BackOffContext is a backoff policy that stops retrying after the context
 // is canceled.
-type BackOffContext interface {
+type BackOffContext interface { // nolint: golint
 	BackOff
 	Context() context.Context
 }
@@ -20,7 +20,7 @@ type backOffContext struct {
 // WithContext returns a BackOffContext with context ctx
 //
 // ctx must not be nil
-func WithContext(b BackOff, ctx context.Context) BackOffContext {
+func WithContext(b BackOff, ctx context.Context) BackOffContext { // nolint: golint
 	if ctx == nil {
 		panic("nil context")
 	}
@@ -38,11 +38,14 @@ func WithContext(b BackOff, ctx context.Context) BackOffContext {
 	}
 }
 
-func ensureContext(b BackOff) BackOffContext {
+func getContext(b BackOff) context.Context {
 	if cb, ok := b.(BackOffContext); ok {
-		return cb
+		return cb.Context()
 	}
-	return WithContext(b, context.Background())
+	if tb, ok := b.(*backOffTries); ok {
+		return getContext(tb.delegate)
+	}
+	return context.Background()
 }
 
 func (b *backOffContext) Context() context.Context {
@@ -54,10 +57,6 @@ func (b *backOffContext) NextBackOff() time.Duration {
 	case <-b.ctx.Done():
 		return Stop
 	default:
+		return b.BackOff.NextBackOff()
 	}
-	next := b.BackOff.NextBackOff()
-	if deadline, ok := b.ctx.Deadline(); ok && deadline.Sub(time.Now()) < next {
-		return Stop
-	}
-	return next
 }

vendor/github.com/cenkalti/backoff/exponential.go → vendor/github.com/cenkalti/backoff/v4/exponential.go

@@ -56,9 +56,10 @@ type ExponentialBackOff struct {
 	RandomizationFactor float64
 	Multiplier          float64
 	MaxInterval         time.Duration
-	// After MaxElapsedTime the ExponentialBackOff stops.
+	// After MaxElapsedTime the ExponentialBackOff returns Stop.
 	// It never stops if MaxElapsedTime == 0.
 	MaxElapsedTime time.Duration
+	Stop           time.Duration
 	Clock          Clock
 
 	currentInterval time.Duration
@@ -87,6 +88,7 @@ func NewExponentialBackOff() *ExponentialBackOff {
 		Multiplier:          DefaultMultiplier,
 		MaxInterval:         DefaultMaxInterval,
 		MaxElapsedTime:      DefaultMaxElapsedTime,
+		Stop:                Stop,
 		Clock:               SystemClock,
 	}
 	b.Reset()
@@ -103,20 +105,23 @@ func (t systemClock) Now() time.Time {
 var SystemClock = systemClock{}
 
 // Reset the interval back to the initial retry interval and restarts the timer.
+// Reset must be called before using b.
 func (b *ExponentialBackOff) Reset() {
 	b.currentInterval = b.InitialInterval
 	b.startTime = b.Clock.Now()
 }
 
 // NextBackOff calculates the next backoff interval using the formula:
-// 	Randomized interval = RetryInterval +/- (RandomizationFactor * RetryInterval)
+// 	Randomized interval = RetryInterval * (1 ± RandomizationFactor)
 func (b *ExponentialBackOff) NextBackOff() time.Duration {
 	// Make sure we have not gone over the maximum elapsed time.
-	if b.MaxElapsedTime != 0 && b.GetElapsedTime() > b.MaxElapsedTime {
-		return Stop
+	elapsed := b.GetElapsedTime()
+	next := getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
+	b.incrementCurrentInterval()
+	if b.MaxElapsedTime != 0 && elapsed+next > b.MaxElapsedTime {
+		return b.Stop
 	}
-	defer b.incrementCurrentInterval()
-	return getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
+	return next
 }
 
 // GetElapsedTime returns the elapsed time since an ExponentialBackOff instance
@@ -140,8 +145,11 @@ func (b *ExponentialBackOff) incrementCurrentInterval() {
 }
 
 // Returns a random value from the following interval:
-// 	[randomizationFactor * currentInterval, randomizationFactor * currentInterval].
+// 	[currentInterval - randomizationFactor * currentInterval, currentInterval + randomizationFactor * currentInterval].
 func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
+	if randomizationFactor == 0 {
+		return currentInterval // make sure no randomness is used when randomizationFactor is 0.
+	}
 	var delta = randomizationFactor * float64(currentInterval)
 	var minInterval = float64(currentInterval) - delta
 	var maxInterval = float64(currentInterval) + delta

vendor/github.com/cenkalti/backoff/retry.go → vendor/github.com/cenkalti/backoff/v4/retry.go

 package backoff
 
-import "time"
+import (
+	"errors"
+	"time"
+)
 
 // An Operation is executing by Retry() or RetryNotify().
 // The operation will be retried using a backoff policy if it returns an error.
@@ -21,16 +24,31 @@ type Notify func(error, time.Duration)
 //
 // Retry sleeps the goroutine for the duration returned by BackOff after a
 // failed operation returns.
-func Retry(o Operation, b BackOff) error { return RetryNotify(o, b, nil) }
+func Retry(o Operation, b BackOff) error {
+	return RetryNotify(o, b, nil)
+}
 
 // RetryNotify calls notify function with the error and wait duration
 // for each failed attempt before sleep.
 func RetryNotify(operation Operation, b BackOff, notify Notify) error {
+	return RetryNotifyWithTimer(operation, b, notify, nil)
+}
+
+// RetryNotifyWithTimer calls notify function with the error and wait duration using the given Timer
+// for each failed attempt before sleep.
+// A default timer that uses system timer is used when nil is passed.
+func RetryNotifyWithTimer(operation Operation, b BackOff, notify Notify, t Timer) error {
 	var err error
 	var next time.Duration
-	var t *time.Timer
+	if t == nil {
+		t = &defaultTimer{}
+	}
+
+	defer func() {
+		t.Stop()
+	}()
 
-	cb := ensureContext(b)
+	ctx := getContext(b)
 
 	b.Reset()
 	for {
@@ -38,11 +56,16 @@ func RetryNotify(operation Operation, b BackOff, notify Notify) error {
 			return nil
 		}
 
-		if permanent, ok := err.(*PermanentError); ok {
+		var permanent *PermanentError
+		if errors.As(err, &permanent) {
 			return permanent.Err
 		}
 
-		if next = cb.NextBackOff(); next == Stop {
+		if next = b.NextBackOff(); next == Stop {
+			if cerr := ctx.Err(); cerr != nil {
+				return cerr
+			}
+
 			return err
 		}
 
@@ -50,17 +73,12 @@ func RetryNotify(operation Operation, b BackOff, notify Notify) error {
 			notify(err, next)
 		}
 
-		if t == nil {
-			t = time.NewTimer(next)
-			defer t.Stop()
-		} else {
-			t.Reset(next)
-		}
+		t.Start(next)
 
 		select {
-		case <-cb.Context().Done():
-			return err
-		case <-t.C:
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-t.C():
 		}
 	}
 }
@@ -74,8 +92,20 @@ func (e *PermanentError) Error() string {
 	return e.Err.Error()
 }
 
+func (e *PermanentError) Unwrap() error {
+	return e.Err
+}
+
+func (e *PermanentError) Is(target error) bool {
+	_, ok := target.(*PermanentError)
+	return ok
+}
+
 // Permanent wraps the given err in a *PermanentError.
-func Permanent(err error) *PermanentError {
+func Permanent(err error) error {
+	if err == nil {
+		return nil
+	}
 	return &PermanentError{
 		Err: err,
 	}

vendor/github.com/cenkalti/backoff/ticker.go → vendor/github.com/cenkalti/backoff/v4/ticker.go

 package backoff
 
 import (
+	"context"
 	"sync"
 	"time"
 )
@@ -12,7 +13,9 @@ import (
 type Ticker struct {
 	C        <-chan time.Time
 	c        chan time.Time
-	b        BackOffContext
+	b        BackOff
+	ctx      context.Context
+	timer    Timer
 	stop     chan struct{}
 	stopOnce sync.Once
 }
@@ -24,11 +27,22 @@ type Ticker struct {
 // provided backoff policy (notably calling NextBackOff or Reset)
 // while the ticker is running.
 func NewTicker(b BackOff) *Ticker {
+	return NewTickerWithTimer(b, &defaultTimer{})
+}
+
+// NewTickerWithTimer returns a new Ticker with a custom timer.
+// A default timer that uses system timer is used when nil is passed.
+func NewTickerWithTimer(b BackOff, timer Timer) *Ticker {
+	if timer == nil {
+		timer = &defaultTimer{}
+	}
 	c := make(chan time.Time)
 	t := &Ticker{
 		C:     c,
 		c:     c,
-		b:    ensureContext(b),
+		b:     b,
+		ctx:   getContext(b),
+		timer: timer,
 		stop:  make(chan struct{}),
 	}
 	t.b.Reset()
@@ -59,7 +73,7 @@ func (t *Ticker) run() {
 		case <-t.stop:
 			t.c = nil // Prevent future ticks from being sent to the channel.
 			return
-		case <-t.b.Context().Done():
+		case <-t.ctx.Done():
 			return
 		}
 	}
@@ -78,5 +92,6 @@ func (t *Ticker) send(tick time.Time) <-chan time.Time {
 		return nil
 	}
 
-	return time.After(next)
+	t.timer.Start(next)
+	return t.timer.C()
 }

vendor/github.com/cenkalti/backoff/v4/timer.go

+package backoff
+
+import "time"
+
+type Timer interface {
+	Start(duration time.Duration)
+	Stop()
+	C() <-chan time.Time
+}
+
+// defaultTimer implements Timer interface using time.Timer
+type defaultTimer struct {
+	timer *time.Timer
+}
+
+// C returns the timers channel which receives the current time when the timer fires.
+func (t *defaultTimer) C() <-chan time.Time {
+	return t.timer.C
+}
+
+// Start starts the timer to fire after the given duration
+func (t *defaultTimer) Start(duration time.Duration) {
+	if t.timer == nil {
+		t.timer = time.NewTimer(duration)
+	} else {
+		t.timer.Reset(duration)
+	}
+}
+
+// Stop is called when the timer is not used anymore and resources may be freed.
+func (t *defaultTimer) Stop() {
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+}

vendor/github.com/cenkalti/backoff/tries.go → vendor/github.com/cenkalti/backoff/v4/tries.go

@@ -20,6 +20,9 @@ type backOffTries struct {
 }
 
 func (b *backOffTries) NextBackOff() time.Duration {
+	if b.maxTries == 0 {
+		return Stop
+	}
 	if b.maxTries > 0 {
 		if b.maxTries <= b.numTries {
 			return Stop

vendor/github.com/cespare/xxhash/v2/.travis.yml

-language: go
-go:
-  - "1.x"
-  - master
-env:
-  - TAGS=""
-  - TAGS="-tags purego"
-script: go test $TAGS -v ./...

vendor/github.com/cespare/xxhash/v2/README.md

 # xxhash
 
-[![GoDoc](https://godoc.org/github.com/cespare/xxhash?status.svg)](https://godoc.org/github.com/cespare/xxhash)
-[![Build Status](https://travis-ci.org/cespare/xxhash.svg?branch=master)](https://travis-ci.org/cespare/xxhash)
+[![Go Reference](https://pkg.go.dev/badge/github.com/cespare/xxhash/v2.svg)](https://pkg.go.dev/github.com/cespare/xxhash/v2)
+[![Test](https://github.com/cespare/xxhash/actions/workflows/test.yml/badge.svg)](https://github.com/cespare/xxhash/actions/workflows/test.yml)
 
 xxhash is a Go implementation of the 64-bit
 [xxHash](http://cyan4973.github.io/xxHash/) algorithm, XXH64. This is a
@@ -64,4 +64,6 @@ $ go test -benchtime 10s -bench '/xxhash,direct,bytes'
 
 - [InfluxDB](https://github.com/influxdata/influxdb)
 - [Prometheus](https://github.com/prometheus/prometheus)
+- [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics)
 - [FreeCache](https://github.com/coocood/freecache)
+- [FastCache](https://github.com/VictoriaMetrics/fastcache)

vendor/github.com/cespare/xxhash/v2/go.mod

-module github.com/cespare/xxhash/v2
-
-go 1.11

vendor/github.com/cespare/xxhash/v2/xxhash.go

@@ -193,7 +193,6 @@ func (d *Digest) UnmarshalBinary(b []byte) error {
 	b, d.v4 = consumeUint64(b)
 	b, d.total = consumeUint64(b)
 	copy(d.mem[:], b)
-	b = b[len(d.mem):]
 	d.n = int(d.total % uint64(len(d.mem)))
 	return nil
 }

vendor/github.com/cespare/xxhash/v2/xxhash_amd64.s

@@ -6,7 +6,7 @@
 
 // Register allocation:
 // AX	h
-// CX	pointer to advance through b
+// SI	pointer to advance through b
 // DX	n
 // BX	loop end
 // R8	v1, k1
@@ -16,39 +16,39 @@
 // R12	tmp
 // R13	prime1v
 // R14	prime2v
-// R15	prime4v
+// DI	prime4v
 
-// round reads from and advances the buffer pointer in CX.
+// round reads from and advances the buffer pointer in SI.
 // It assumes that R13 has prime1v and R14 has prime2v.
 #define round(r) \
-	MOVQ  (CX), R12 \
-	ADDQ  $8, CX    \
+	MOVQ  (SI), R12 \
+	ADDQ  $8, SI    \
 	IMULQ R14, R12  \
 	ADDQ  R12, r    \
 	ROLQ  $31, r    \
 	IMULQ R13, r
 
 // mergeRound applies a merge round on the two registers acc and val.
-// It assumes that R13 has prime1v, R14 has prime2v, and R15 has prime4v.
+// It assumes that R13 has prime1v, R14 has prime2v, and DI has prime4v.
 #define mergeRound(acc, val) \
 	IMULQ R14, val \
 	ROLQ  $31, val \
 	IMULQ R13, val \
 	XORQ  val, acc \
 	IMULQ R13, acc \
-	ADDQ  R15, acc
+	ADDQ  DI, acc
 
 // func Sum64(b []byte) uint64
 TEXT ·Sum64(SB), NOSPLIT, $0-32
 	// Load fixed primes.
 	MOVQ ·prime1v(SB), R13
 	MOVQ ·prime2v(SB), R14
-	MOVQ ·prime4v(SB), R15
+	MOVQ ·prime4v(SB), DI
 
 	// Load slice.
-	MOVQ b_base+0(FP), CX
+	MOVQ b_base+0(FP), SI
 	MOVQ b_len+8(FP), DX
-	LEAQ (CX)(DX*1), BX
+	LEAQ (SI)(DX*1), BX
 
 	// The first loop limit will be len(b)-32.
 	SUBQ $32, BX
@@ -65,14 +65,14 @@ TEXT ·Sum64(SB), NOSPLIT, $0-32
 	XORQ R11, R11
 	SUBQ R13, R11
 
-	// Loop until CX > BX.
+	// Loop until SI > BX.
 blockLoop:
 	round(R8)
 	round(R9)
 	round(R10)
 	round(R11)
 
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JLE  blockLoop
 
 	MOVQ R8, AX
@@ -100,16 +100,16 @@ noBlocks:
 afterBlocks:
 	ADDQ DX, AX
 
-	// Right now BX has len(b)-32, and we want to loop until CX > len(b)-8.
+	// Right now BX has len(b)-32, and we want to loop until SI > len(b)-8.
 	ADDQ $24, BX
 
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JG   fourByte
 
 wordLoop:
 	// Calculate k1.
-	MOVQ  (CX), R8
-	ADDQ  $8, CX
+	MOVQ  (SI), R8
+	ADDQ  $8, SI
 	IMULQ R14, R8
 	ROLQ  $31, R8
 	IMULQ R13, R8
@@ -117,18 +117,18 @@ wordLoop:
 	XORQ  R8, AX
 	ROLQ  $27, AX
 	IMULQ R13, AX
-	ADDQ  R15, AX
+	ADDQ  DI, AX
 
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JLE  wordLoop
 
 fourByte:
 	ADDQ $4, BX
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JG   singles
 
-	MOVL  (CX), R8
-	ADDQ  $4, CX
+	MOVL  (SI), R8
+	ADDQ  $4, SI
 	IMULQ R13, R8
 	XORQ  R8, AX
 
@@ -138,19 +138,19 @@ fourByte:
 
 singles:
 	ADDQ $4, BX
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JGE  finalize
 
 singlesLoop:
-	MOVBQZX (CX), R12
-	ADDQ    $1, CX
+	MOVBQZX (SI), R12
+	ADDQ    $1, SI
 	IMULQ   ·prime5v(SB), R12
 	XORQ    R12, AX
 
 	ROLQ  $11, AX
 	IMULQ R13, AX
 
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JL   singlesLoop
 
 finalize:
@@ -179,9 +179,9 @@ TEXT ·writeBlocks(SB), NOSPLIT, $0-40
 	MOVQ ·prime2v(SB), R14
 
 	// Load slice.
-	MOVQ b_base+8(FP), CX
+	MOVQ b_base+8(FP), SI
 	MOVQ b_len+16(FP), DX
-	LEAQ (CX)(DX*1), BX
+	LEAQ (SI)(DX*1), BX
 	SUBQ $32, BX
 
 	// Load vN from d.
@@ -199,7 +199,7 @@ blockLoop:
 	round(R10)
 	round(R11)
 
-	CMPQ CX, BX
+	CMPQ SI, BX
 	JLE  blockLoop
 
 	// Copy vN back to d.
@@ -208,8 +208,8 @@ blockLoop:
 	MOVQ R10, 16(AX)
 	MOVQ R11, 24(AX)
 
-	// The number of bytes written is CX minus the old base pointer.
-	SUBQ b_base+8(FP), CX
-	MOVQ CX, ret+32(FP)
+	// The number of bytes written is SI minus the old base pointer.
+	SUBQ b_base+8(FP), SI
+	MOVQ SI, ret+32(FP)
 
 	RET

vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go

@@ -6,41 +6,52 @@
 package xxhash
 
 import (
-	"reflect"
 	"unsafe"
 )
 
-// Notes:
+// In the future it's possible that compiler optimizations will make these
+// XxxString functions unnecessary by realizing that calls such as
+// Sum64([]byte(s)) don't need to copy s. See https://golang.org/issue/2205.
+// If that happens, even if we keep these functions they can be replaced with
+// the trivial safe code.
+
+// NOTE: The usual way of doing an unsafe string-to-[]byte conversion is:
 //
-// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
-// for some discussion about these unsafe conversions.
+//   var b []byte
+//   bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+//   bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
+//   bh.Len = len(s)
+//   bh.Cap = len(s)
 //
-// In the future it's possible that compiler optimizations will make these
-// unsafe operations unnecessary: https://golang.org/issue/2205.
+// Unfortunately, as of Go 1.15.3 the inliner's cost model assigns a high enough
+// weight to this sequence of expressions that any function that uses it will
+// not be inlined. Instead, the functions below use a different unsafe
+// conversion designed to minimize the inliner weight and allow both to be
+// inlined. There is also a test (TestInlining) which verifies that these are
+// inlined.
 //
-// Both of these wrapper functions still incur function call overhead since they
-// will not be inlined. We could write Go/asm copies of Sum64 and Digest.Write
-// for strings to squeeze out a bit more speed. Mid-stack inlining should
-// eventually fix this.
+// See https://github.com/golang/go/issues/42739 for discussion.
 
 // Sum64String computes the 64-bit xxHash digest of s.
 // It may be faster than Sum64([]byte(s)) by avoiding a copy.
 func Sum64String(s string) uint64 {
-	var b []byte
-	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
-	bh.Len = len(s)
-	bh.Cap = len(s)
+	b := *(*[]byte)(unsafe.Pointer(&sliceHeader{s, len(s)}))
 	return Sum64(b)
 }
 
 // WriteString adds more data to d. It always returns len(s), nil.
 // It may be faster than Write([]byte(s)) by avoiding a copy.
 func (d *Digest) WriteString(s string) (n int, err error) {
-	var b []byte
-	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
-	bh.Len = len(s)
-	bh.Cap = len(s)
-	return d.Write(b)
+	d.Write(*(*[]byte)(unsafe.Pointer(&sliceHeader{s, len(s)})))
+	// d.Write always returns len(s), nil.
+	// Ignoring the return output and returning these fixed values buys a
+	// savings of 6 in the inliner's cost model.
+	return len(s), nil
+}
+
+// sliceHeader is similar to reflect.SliceHeader, but it assumes that the layout
+// of the first two words is the same as the layout of a string.
+type sliceHeader struct {
+	s   string
+	cap int
 }

vendor/github.com/coreos/go-systemd/v22/daemon/watchdog.go

@@ -30,8 +30,8 @@ import (
 // It returns one of the following:
 // (0, nil) - watchdog isn't enabled or we aren't the watched PID.
 // (0, err) - an error happened (e.g. error converting time).
-// (time, nil) - watchdog is enabled and we can send ping.
-//   time is delay before inactive service will be killed.
+// (time, nil) - watchdog is enabled and we can send ping.  time is delay
+// before inactive service will be killed.
 func SdWatchdogEnabled(unsetEnvironment bool) (time.Duration, error) {
 	wusec := os.Getenv("WATCHDOG_USEC")
 	wpid := os.Getenv("WATCHDOG_PID")

vendor/github.com/felixge/httpsnoop/README.md

@@ -65,7 +65,8 @@ being called, or called more than once, as well as concurrent calls to
 Unfortunately this package is not perfect either. It's possible that it is
 still missing some interfaces provided by the go core (let me know if you find
 one), and it won't work for applications adding their own interfaces into the
-mix.
+mix. You can however use `httpsnoop.Unwrap(w)` to access the underlying
+`http.ResponseWriter` and type-assert the result to its other interfaces.
 
 However, hopefully the explanation above has sufficiently scared you of rolling
 your own solution to this problem. httpsnoop may still break your application,