protected final CountDownLatch listenerLatch = new CountDownLatch(1);

  protected volatile boolean throwException = false;

  protected final ListenableFutureTask<Integer> task =
      ListenableFutureTask.create(
          new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
              runLatch.countDown();
              taskLatch.await();

  protected final CountDownLatch listenerLatch = new CountDownLatch(1);

  protected volatile boolean throwException = false;

  protected final ListenableFutureTask<Integer> task =
      ListenableFutureTask.create(
          new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
              runLatch.countDown();
              taskLatch.await();

    return new SequentialExecutor(delegate);
  }

  /**
   * Creates an {@link ExecutorService} whose {@code submit} and {@code invokeAll} methods submit
   * {@link ListenableFutureTask} instances to the given delegate executor. Those methods, as well
   * as {@code execute} and {@code invokeAny}, are implemented in terms of calls to {@code