private final ArtifactTransferListener listener;

    private final Map<Resource, ArtifactTransferResource> artifacts;

    private final Map<Resource, Long> transfers;

    public static TransferListener newAdapter(ArtifactTransferListener listener) {
        if (listener == null) {
            return null;
        } else {
            return new TransferListenerAdapter(listener);
        }
    }

    Listener listener;
    synchronized (this) {
      listener = listeners.get(state);
    }

    if (code == null || listener == null) {
      return new MockResponse()
          .setResponseCode(404)
          .setBody("unexpected request");
    }

    try {
      OAuthSession session = slackApi.exchangeCode(code, redirectUrl());
      listener.sessionGranted(session);

   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in
   * @throws RejectedExecutionException if we tried to execute the listener immediately but the
   *     executor rejected it.
   */
  void addListener(Runnable listener, Executor executor);

        // Add shutdown listener
        TestShutdownListener listener = new TestShutdownListener();
        scriptExecutor.addShutdownListener(listener);

        // Verify listener not called yet
        assertFalse(listener.wasShutdownCalled());

        // Call shutdown
        scriptExecutor.shutdown();

        // Verify listener was called
        assertTrue(listener.wasShutdownCalled());

   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in
   * @throws RejectedExecutionException if we tried to execute the listener immediately but the
   *     executor rejected it.
   */
  void addListener(Runnable listener, Executor executor);

   * after executing them.
   *
   * @param listener the listener to run when the computation is complete
   * @param executor the executor to run the listener in
   * @throws RejectedExecutionException if we tried to execute the listener immediately but the
   *     executor rejected it.
   */
  void addListener(Runnable listener, Executor executor);

        AbstractFutureState<?> future, @Nullable Listener expect, Listener update) {
      return UNSAFE.compareAndSwapObject(future, LISTENERS_OFFSET, expect, update);
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      while (true) {
        Listener listener = future.listenersField;
        if (update == listener) {
          return listener;
        }

        client.processNotification(notification);

        // Verify notification was delivered
        assertTrue(listener.waitForNotification(1000));
        assertNotNull(listener.getLastNotification());
        assertEquals(WitnessEventType.CLIENT_MOVE, listener.getLastNotification().getEventType());

        client.close();
    }

    @Test
    void testUnregistration() throws Exception {

    }

    @Override
    boolean casListeners(
        AbstractFutureState<?> future, @Nullable Listener expect, Listener update) {
      return listenersUpdater.compareAndSet(future, expect, update);
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      return (Listener) listenersUpdater.getAndSet(future, update);
    }

    @Override

     * This method notifies the shutdown listener to perform cleanup operations.
     */
    public void shutdown() {
        shutdownListener.onShutdown();
    }

    /**
     * Adds a shutdown listener to be notified when the executor is shutting down.
     *
     * @param listener the shutdown listener to add
     */
    public void addShutdownListener(final ShutdownListener listener) {
        shutdownListener = listener;