// If block is true, Read and Write will block when there is no data to read or no space to write.
// If block is false, Read and Write will return ErrIsEmpty or ErrIsFull immediately.
// By default, the ring buffer is not blocking.
// This setting should be called before any Read or Write operation or after a Reset.
func (r *RingBuffer) SetBlocking(block bool) *RingBuffer {
	r.block = block
	if block {

 * test with reference to the same "lock-like object", and then their interactions with that object
 * are choreographed via the various methods on this class.
 *
 * <p>A "lock-like object" is really any object that may be used for concurrency control. If the
 * {@link #callAndAssertBlocks} method is ever called in a test, the lock-like object must have a
 * method equivalent to {@link java.util.concurrent.locks.ReentrantLock#hasQueuedThread(Thread)}. If

     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;
        this.currentFuture = currentFuture;
      }

type NetLocker interface {
	// Do read lock for given LockArgs.  It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.
	RLock(ctx context.Context, args LockArgs) (bool, error)

	// Do write lock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.

   */
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;
    }
  }

	}
}

// Test lock race
func TestNSLockRace(t *testing.T) {
	t.Skip("long test skip it")

	ctx := t.Context()

	for i := range 10000 {
		nsLk := newNSLock(false)

		// lk1; ref=1
		if !nsLk.lock(ctx, "volume", "path", "source", "opsID", false, time.Second) {
			t.Fatal("failed to acquire lock")
		}

		// lk2
		lk2ch := make(chan struct{})
		go func() {

			Op:   "open",
			Path: path,
			Err:  syscall.EINVAL,
		}
	}

	lock := syscall.Flock_t{
		Start:  0,
		Len:    0,
		Pid:    0,
		Type:   lockType,
		Whence: 0,
	}

	f, err := os.OpenFile(path, flag, perm)
	if err != nil {
		return nil, err
	}

	if err = syscall.FcntlFlock(f.Fd(), rlockType, &lock); err != nil {
		f.Close()
		if err == syscall.EAGAIN {
			err = ErrAlreadyLocked
		}

			return
		}
	}
}

func (m *Monitor) updateMovingAvg() {
	m.mlock.Lock()
	defer m.mlock.Unlock()
	for _, bucketMeasurement := range m.bucketsMeasurement {
		bucketMeasurement.updateExponentialMovingAverage(time.Now())
	}
}

func (m *Monitor) init(opts BucketOptions) {
	m.mlock.Lock()
	defer m.mlock.Unlock()

	_, ok := m.bucketsMeasurement[opts]
	if !ok {

		}()

		dm3rd.Lock(id, source)

		// fmt.Printf("3rd lock obtained after 1st & 2nd locks are released\n")
		time.Sleep(testDrwMutexRefreshCallTimeout)

		dm3rd.Unlock(t.Context())
	}()
	expect += 2*testDrwMutexAcquireTimeout + testDrwMutexRefreshCallTimeout

	go func() {
		defer wg.Done()

		dm3rd.Lock(id, source)

		// Release lock after 10 seconds
		go func() {

            lock.readLock().unlock();
        }
    }

    /**
     * Get handle information by path
     * @param path the file path
     * @return the handle info or null if not found
     */
    public HandleInfo getHandleByPath(String path) {
        lock.readLock().lock();
        try {
            return handles.get(path);
        } finally {
            lock.readLock().unlock();
        }
    }