queue.enqueue(incrementingEvent(counters, listener1, 1));
    queue.enqueue(incrementingEvent(counters, listener1, 2));

    Object listener2 = new Object();
    queue.addListener(listener2, directExecutor());
    queue.enqueue(incrementingEvent(counters, multiset(listener1, 3, listener2, 1)));
    queue.enqueue(incrementingEvent(counters, multiset(listener1, 4, listener2, 2)));
    assertEquals(0, counters.size());
    queue.dispatch();

  QueuingRemovalListener<Object, Object> listener;

  @Override
  protected void setUp() {
    listener = queuingRemovalListener();
  }

  public void testGet() {
    Object computed = new Object();
    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder()
            .maximumSize(0)
            .removalListener(listener)
            .build(constantLoader(computed));

      throw exception;
    }
  }

  private static class RecordingListener extends Listener {
    static RecordingListener record(Service service) {
      RecordingListener listener = new RecordingListener(service);
      service.addListener(listener, directExecutor());
      return listener;
    }

    final Service service;

    RecordingListener(Service service) {

    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

    future.set(1);
    listener.assertRun();
  }

  public void testListenLaterFailed() {
    CountingRunnable listener = new CountingRunnable();

    future.addListener(listener, directExecutor());
    listener.assertNotRun();

  }

  /**
   * Verify that the listener completes in a reasonable amount of time, and Asserts that the future
   * returns the expected data.
   *
   * @throws Throwable if the listener isn't called or if it resulted in a throwable or if the
   *     result doesn't match the expected value.
   */
  public void assertSuccess(Object expectedData) throws Throwable {
    // Verify that the listener executed in a reasonable amount of time.

  private static final ListenerCallQueue.Event<Listener> STARTING_EVENT =
      new ListenerCallQueue.Event<Listener>() {
        @Override
        public void call(Listener listener) {
          listener.starting();
        }

        @Override
        public String toString() {
          return "starting()";
        }
      };
  private static final ListenerCallQueue.Event<Listener> RUNNING_EVENT =

  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void addListener(Runnable listener, Executor executor) {
    checkNotNull(listener, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");
    try {
      executor.execute(listener);
    } catch (Exception e) { // sneaky checked exception

  /**
   * Registers a listener to be {@linkplain Executor#execute(Runnable) run} on the given executor.
   * The listener will run when the {@code Future}'s computation is {@linkplain Future#isDone()
   * complete} or, if the computation is already complete, immediately.
   *
   * <p>There is no guaranteed ordering of execution of listeners, but any listener added through

  private CountDownLatch listenerLatch;
  private ExecutionListWrapper list;

  @Param Impl impl;

  @Param({"1", "5", "10"})
  int numListeners;

  private final Runnable listener =
      new Runnable() {
        @Override
        public void run() {
          listenerLatch.countDown();
        }
      };

  @BeforeExperiment
  void setUp() throws Exception {

      while (true) {
        Listener listener = future.listeners;
        if (update == listener) {
          return listener;
        }
        if (casListeners(future, listener, update)) {
          return listener;
        }
      }
    }

    /** Performs a GAS operation on the {@link #waiters} field. */
    @Override
    Waiter gasWaiters(AbstractFuture<?> future, Waiter update) {
      while (true) {