// reads are running.
type syncReadCloser struct {
	rc io.ReadCloser
	mu sync.Mutex
}

func (pr *syncReadCloser) Read(p []byte) (n int, err error) {
	// This ensures that Close will block until Read has completed.
	// This allows another goroutine to close the reader.
	pr.mu.Lock()
	defer pr.mu.Unlock()
	if pr.rc == nil {
		return 0, io.EOF
	}
	return pr.rc.Read(p)
}

	type PaddedMutex struct {
		*DRWMutex
	}
	b.RunParallel(func(pb *testing.PB) {
		mu := PaddedMutex{NewDRWMutex(ds, "")}
		for pb.Next() {
			mu.Lock(id, source)
			mu.Unlock(b.Context())
		}
	})
}

func benchmarkMutex(b *testing.B, slack, work bool) {
	b.ResetTimer()
	b.ReportAllocs()

	mu := NewDRWMutex(ds, "")
	if slack {
		b.SetParallelism(10)
	}

		ExpirationWorkers: 100,
		TransitionWorkers: 100,
	},
}

type ilmConfig struct {
	mu  sync.RWMutex
	cfg ilm.Config
}

func (c *ilmConfig) getExpirationWorkers() int {
	c.mu.RLock()
	defer c.mu.RUnlock()

	return c.cfg.ExpirationWorkers
}

func (c *ilmConfig) getTransitionWorkers() int {
	c.mu.RLock()
	defer c.mu.RUnlock()

	return c.cfg.TransitionWorkers
}

		debug.PrintStack()
		return metacache{}
	}

	// Grab a write lock, since we create one if we cannot find one.
	b.mu.Lock()
	defer b.mu.Unlock()

	// Check if exists already.
	if c, ok := b.caches[o.ID]; ok {
		c.lastHandout = time.Now()
		b.caches[o.ID] = c
		b.debugf("returning existing %v", o.ID)
		return c
	}

func (c *DeadlineConn) setReadDeadline() {
	// Do not set a Read deadline, if upstream wants to cancel all reads.
	if c.readDeadline <= 0 || c.abortReads.Load() || c.infReads.Load() {
		return
	}

	c.mu.Lock()
	defer c.mu.Unlock()
	if c.abortReads.Load() {
		return
	}

	now := time.Now()
	if now.Sub(c.readSetAt) > updateInterval {
		c.Conn.SetReadDeadline(now.Add(c.readDeadline + updateInterval))
		c.readSetAt = now
	}

	Type() types.TargetType
}

type targetsList struct {
	list []Target
	mu   sync.RWMutex
}

func newTargetsList() *targetsList {
	return &targetsList{}
}

func (tl *targetsList) get() []Target {
	tl.mu.RLock()
	defer tl.mu.RUnlock()

	return tl.list
}

func (tl *targetsList) add(t Target) {
	tl.mu.Lock()
	defer tl.mu.Unlock()

	tl.list = append(tl.list, t)
}

type disconnectReader struct {
	r  io.Reader
	mu sync.Mutex
}

func (d *disconnectReader) Read(p []byte) (n int, err error) {
	d.mu.Lock()
	defer d.mu.Unlock()
	if d.r != nil {
		return d.r.Read(p)
	}
	return 0, errors.New("reader closed")
}

func (d *disconnectReader) Close() error {
	d.mu.Lock()
	d.r = nil
	d.mu.Unlock()
	return nil
}

	// Return a transient bucket for invalid or system buckets.
	m.mu.RLock()
	b, ok := m.buckets[bucket]
	if ok {
		m.mu.RUnlock()
		if b.bucket != bucket {
			logger.Info("getBucket: cached bucket %s does not match this bucket %s", b.bucket, bucket)
			debug.PrintStack()
		}
		return b
	}

	m.mu.RUnlock()
	m.mu.Lock()
	defer m.mu.Unlock()
	// See if someone else fetched it while we waited for the lock.

	const isWriteLock = false
	return lm.lockLoop(ctx, id, source, timeout, isWriteLock)
}

func (lm *LRWMutex) lock(id, source string, isWriteLock bool) (locked bool) {
	lm.mu.Lock()
	defer lm.mu.Unlock()

	lm.id = id
	lm.source = source
	if isWriteLock {
		if lm.ref == 0 && !lm.isWriteLock {
			lm.ref = 1
			lm.isWriteLock = true
			locked = true
		}
	} else {
		if !lm.isWriteLock {

	var incorrectConfigs []error
	var retries int
	var mu sync.Mutex
	for onlineServers < len(clnts)/2 {
		var wg sync.WaitGroup
		wg.Add(len(clnts))
		onlineServers = 0
		for _, clnt := range clnts {
			go func(clnt *bootstrapRESTClient) {
				defer wg.Done()

				if clnt.gridConn.State() != grid.StateConnected {
					mu.Lock()