// and positive values indicating number of read locks
	lockMap map[string]int64

	// Refresh returns lock not found if set to true
	lockNotFound bool

	// Set to true if you want peers servers to do not respond
	responseDelay int64
}

func (l *lockServer) setRefreshReply(refreshed bool) {
	l.mutex.Lock()
	defer l.mutex.Unlock()

   */
  @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;
    }
  }

	}
}

// Lock holds a write lock on dm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (dm *DRWMutex) Lock(id, source string) {
	isReadLock := false
	dm.lockBlocking(context.Background(), nil, id, source, isReadLock, Options{
		Timeout: drwMutexInfinite,
	})
}

// Options lock options.
type Options struct {

	Source          string // Contains line, function and filename requesting the lock.
	Group           bool   // indicates if it was a group lock.
	Owner           string // Owner represents the UUID of the owner who originally requested the lock.
	Quorum          int    // Quorum represents the quorum required for this lock to be active.
	idx             int    `msg:"-"` // index of the lock in the lockMap.
}

            }
        } finally {
            lock.writeLock().unlock();
        }
    }

    /**
     * Remove a child entry
     *
     * @param childName child file name
     */
    public void removeChild(String childName) {
        lock.writeLock().lock();
        try {
            if (children.remove(childName) != null) {

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.

     * 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;
      }

   *
   * Lock lockA = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockB = factory1.newReentrantLock(MyLockOrder.FIRST);
   * Lock lockC = factory2.newReentrantLock(MyLockOrder.FIRST);
   *
   * lockA.lock();
   *
   * lockB.lock();  // will throw an IllegalStateException
   * lockC.lock();  // will throw an IllegalStateException
   *
   * lockA.lock();  // reentrant acquisition is okay
   * }

					}

					toUnLock = toUnLock[:0]
					for k, v := range l.lockMap {
						for _, lock := range v {
							toUnLock = append(toUnLock, dsync.LockArgs{Resources: []string{k}, UID: lock.UID, Owner: lock.Owner})
						}
					}
					start = time.Now()
					for _, lock := range toUnLock {
						ok, err := l.RUnlock(t.Context(), lock)
						if err != nil || !ok {
							t.Fatal(err)
						}
					}

			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
		}