mg.ExtraLabels)
	for _, metric := range promMetrics {
		ch <- metric
	}
}

// LockAndSetBuckets - locks the buckets and sets the given buckets. It returns
// a function to unlock the buckets.
func (mg *MetricsGroup) LockAndSetBuckets(buckets []string) func() {
	mg.bucketsLock.Lock()
	mg.buckets = buckets
	return func() {
		mg.bucketsLock.Unlock()
	}
}

	CreatedAt         time.Time // only for site replication
	NoLock            bool      // does not lock the make bucket call if set to 'true'
}

// DeleteBucketOptions provides options for DeleteBucket calls.
type DeleteBucketOptions struct {
	NoLock     bool             // does not lock the delete bucket call if set to 'true'
	NoRecreate bool             // do not recreate bucket on delete failures

	return metrics
}

func (config *TierConfigMgr) refreshedAt() time.Time {
	config.RLock()
	defer config.RUnlock()
	return config.lastRefreshedAt
}

// IsTierValid returns true if there exists a remote tier by name tierName,
// otherwise returns false.
func (config *TierConfigMgr) IsTierValid(tierName string) bool {
	config.RLock()
	defer config.RUnlock()
	_, valid := config.isTierNameInUse(tierName)
	return valid

	}

	cert, ok := clientKey.(*ssh.Certificate)
	if !ok {
		return errSftpPublicKeyWithoutCert
	}

	// ssh.CheckCert called by ssh.Authenticate accepts certificates
	// with empty principles list so we block those in here.
	if len(cert.ValidPrincipals) == 0 {
		return errSftpCertWithoutPrincipals
	}

	// Verify that certificate provided by user is issued by trusted CA,

*   Adds `Dataset.interleave` transformation.
*   Add `ConcatenateDataset` to concatenate two datasets.
*   Added Mobilenet support to TensorFlow for Poets training script.
*   Adds a block cache to the GCS filesystem with configurable block size and
    count.
*   SinhArcSinh bijector added.
*   Added `Dataset.list_files` API.
*   Introduces new operations and Python bindings for the Cloud TPU.

   * BiMap<Long, String> map = Maps.synchronizedBiMap(HashBiMap.create());
   * ...
   * Set<Long> set = map.keySet();  // Needn't be in synchronized block
   * ...
   * synchronized (map) {  // Synchronizing on map, not set!
   *   Iterator<Long> it = set.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
   *

   * BiMap<Long, String> map = Maps.synchronizedBiMap(HashBiMap.create());
   * ...
   * Set<Long> set = map.keySet();  // Needn't be in synchronized block
   * ...
   * synchronized (map) {  // Synchronizing on map, not set!
   *   Iterator<Long> it = set.iterator(); // Must be in synchronized block
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
   *

                // Expected
            }
        }

        assertEquals(State.OPEN, circuitBreaker.getState(), "Circuit should be OPEN");

        // Try to execute - should be blocked with CIFSException
        CIFSException exception = assertThrows(CIFSException.class, () -> {
            circuitBreaker.executeWithCircuitBreaker(() -> "should not execute");

	h.status.Store(statusClosed)
	h.storeCtxCancel()

	// Wait for messages to be sent...
	h.wg.Wait()

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

func addCustomHeadersMiddleware(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		header := w.Header()
		header.Set("X-XSS-Protection", "1; mode=block")                                // Prevents against XSS attacks
		header.Set("X-Content-Type-Options", "nosniff")                                // Prevent mime-sniff