* 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;
      }

        MethodMetaData tooManyParams = method('block', classMetaData, paramTypes: ['String', 'boolean'])
        MethodMetaData notAClosure = method('block', classMetaData, paramTypes: ['String'])
        MethodMetaData noBlockProperty = method('notBlock', classMetaData, paramTypes: [Closure.class.name])
        _ * classMetaData.findProperty('block') >> blockProperty

            lock = new Smb2Lock(offset, length, flags);

            assertNotNull(lock);
        }

        @Test
        @DisplayName("Should create lock with zero offset and length")
        void testConstructorWithZeroValues() {
            lock = new Smb2Lock(0L, 0L, 0);

            assertNotNull(lock);
        }

        @Test

	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := z.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()
		nsUnlocker = func() { lock.RUnlock(lkctx) }
		unlockOnDefer = true
	}

	checkPrecondFn := opts.CheckPrecondFn

   *
   * 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
   * }

	dm1st := NewDRWMutex(ds, "aap")
	dm2nd := NewDRWMutex(ds, "aap")

	dm1st.Lock(id, source)

	// Release lock after 10 seconds
	go func() {
		time.Sleep(5 * testDrwMutexAcquireTimeout)
		// fmt.Println("Unlocking dm1")

		dm1st.Unlock(t.Context())
	}()

	dm2nd.Lock(id, source)

	// fmt.Printf("2nd lock obtained after 1st lock is released\n")
	time.Sleep(testDrwMutexRefreshCallTimeout * 2)

    }

    /// Encrypt a block of bytes.
    /**
     * Encrypts an 8-byte block using DES
     * @param clearText the 8-byte plaintext block
     * @param cipherText the output 8-byte ciphertext block
     */
    public void encrypt(final byte[] clearText, final byte[] cipherText) {
        encrypt(clearText, 0, cipherText, 0);
    }

    /// Decrypt a block of bytes.
    /**

    public void releaseLease(Smb2LeaseKey key) {
        lock.writeLock().lock();
        try {
            LeaseEntry entry = leases.remove(key);
            if (entry != null) {
                pathToLease.remove(entry.getPath());
                log.debug("Released lease for path: {} with key: {}", entry.getPath(), key);
            }
        } finally {
            lock.writeLock().unlock();
        }
    }

    /**

            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();
        }
    }

      while (true) {
        var tryAgain = false
        var readBytesDelivered = -1L
        var errorExceptionToDeliver: IOException? = null

        // 1. Decide what to do in a synchronized block.

        withLock {
          val doReadTimeout = doReadTimeout()
          if (doReadTimeout) {
            readTimeout.enter()
          }
          try {