defer func() {
		if recover() == nil {
			t.Fatalf("read unlock of unlocked RWMutex did not panic")
		}
		mu.Unlock(t.Context()) // Unlock, so -test.count > 1 works
	}()
	mu.Lock(id, source)
	mu.RUnlock(t.Context())
}

// Borrowed from rwmutex_test.go
func benchmarkRWMutex(b *testing.B, localWork, writeRatio int) {
	b.ResetTimer()
	b.ReportAllocs()

}

// Empty returns true if targetList is empty.
func (list *TargetList) Empty() bool {
	list.RLock()
	defer list.RUnlock()

	return len(list.targets) == 0
}

// List - returns available target IDs.
func (list *TargetList) List(region string) []ARN {
	list.RLock()
	defer list.RUnlock()

	keys := make([]ARN, 0, len(list.targets))
	for k := range list.targets {

		if recover() == nil {
			t.Fatalf("unlock of unlocked RWMutex did not panic")
		}
	}()
	mu := NewLRWMutex()
	mu.Unlock()
}

// Borrowed from rwmutex_test.go
func TestUnlockPanic2(t *testing.T) {
	defer func() {
		if recover() == nil {
			t.Fatalf("unlock of unlocked RWMutex did not panic")
		}
	}()
	mu := NewLRWMutex()
	mu.RLock()
	mu.Unlock()
}

// Borrowed from rwmutex_test.go

func (lm *LRWMutex) RUnlock() {
	isWriteLock := false
	success := lm.unlock(isWriteLock)
	if !success {
		panic("Trying to RUnlock() while no RLock() is active")
	}
}

func (lm *LRWMutex) unlock(isWriteLock bool) (unlocked bool) {
	lm.mu.Lock()
	defer lm.mu.Unlock()

	// Try to release lock.
	if isWriteLock {
		if lm.isWriteLock && lm.ref == 1 {
			lm.ref = 0

			delete(n.lockMap, resource)
		}
		n.lockMapMutex.Unlock()
	}

	return locked
}

// Unlock the namespace resource.
func (n *nsLockMap) unlock(volume string, path string, readLock bool) {
	resource := pathJoin(volume, path)

	n.lockMapMutex.Lock()
	defer n.lockMapMutex.Unlock()
	if _, found := n.lockMap[resource]; !found {
		return
	}
	if readLock {

// List - returns available target IDs.
func (list *TargetList) List() []TargetID {
	list.RLock()
	defer list.RUnlock()

	keys := []TargetID{}
	for k := range list.targets {
		keys = append(keys, k)
	}

	return keys
}

func (list *TargetList) get(id TargetID) (Target, bool) {
	list.RLock()
	defer list.RUnlock()

	target, ok := list.targets[id]
	return target, ok
}

	// 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.

	m.tlock.Unlock()
	m.mlock.Lock()
	delete(m.bucketsMeasurement, BucketOptions{Name: bucket, ReplicationARN: arn})
	m.mlock.Unlock()
}

// throttle returns currently configured throttle for this bucket
func (m *Monitor) throttle(opts BucketOptions) *bucketThrottle {
	m.tlock.RLock()
	defer m.tlock.RUnlock()
	return m.bucketsThrottle[opts]
}

}

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
}

func (c *ilmConfig) update(cfg ilm.Config) {
	c.mu.Lock()
	defer c.mu.Unlock()

	c.cfg = cfg

// - '> 0' interval duration between cycles
func (opts Config) BitrotScanCycle() (d time.Duration) {
	configMutex.RLock()
	defer configMutex.RUnlock()
	return opts.cache.bitrotCycle
}

// Clone safely the heal configuration
func (opts Config) Clone() (int, time.Duration, string) {
	configMutex.RLock()
	defer configMutex.RUnlock()
	return opts.IOCount, opts.Sleep, opts.Bitrot
}