int iterations = 1000;
        ExecutorService executor = Executors.newFixedThreadPool(2);
        CountDownLatch endLatch = new CountDownLatch(2);
        AtomicInteger successCount = new AtomicInteger(0);
        List<Exception> exceptions = Collections.synchronizedList(new ArrayList<>());

        // Thread 1: Continuously adds trees
        executor.submit(() -> {
            try {

    executor.execute(task);
    return task;
  }

  /**
   * Executes {@code runnable} on the specified {@code executor}, returning a {@code Future} that
   * will complete after execution.
   *
   * @throws RejectedExecutionException if the task cannot be scheduled for execution
   * @since 28.2
   */
  public static ListenableFuture<@Nullable Void> submit(Runnable runnable, Executor executor) {

   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future, Executor executor) {
    checkNotNull(executor);
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future, executor);
  }

  /**
   * An adapter to turn a {@link Future} into a {@link ListenableFuture}. This will wait on the

                  + runnable
                  + " with executor "
                  + executor,
              e);
    }
  }

  private static final class RunnableExecutorPair {
    final Runnable runnable;
    final Executor executor;
    @Nullable RunnableExecutorPair next;

    RunnableExecutorPair(
        Runnable runnable, Executor executor, @Nullable RunnableExecutorPair next) {

                  + runnable
                  + " with executor "
                  + executor,
              e);
    }
  }

  private static final class RunnableExecutorPair {
    final Runnable runnable;
    final Executor executor;
    @Nullable RunnableExecutorPair next;

    RunnableExecutorPair(
        Runnable runnable, Executor executor, @Nullable RunnableExecutorPair next) {

    List<Future<?>> results = new ArrayList<>();
    Runnable[] manualExecutorTask = new Runnable[1];
    Executor manualExecutor =
        new Executor() {
          @Override
          public void execute(Runnable task) {
            manualExecutorTask[0] = task;
          }
        };

    results.add(serializer.submit(Callables.returning(null), manualExecutor));

  private final Service delegate =
      new AbstractService() {
        @Override
        protected final void doStart() {
          Executor executor = renamingDecorator(executor(), () -> serviceName());
          executor.execute(
              () -> {
                try {
                  startUp();
                  notifyStarted();

   *     returned future.
   * @param executor Executor to run the function in.
   * @return A future that holds result of the transformation.
   */
  public final <T extends @Nullable Object> FluentFuture<T> transform(
      Function<? super V, T> function, Executor executor) {
    return (FluentFuture<T>) Futures.transform(this, function, executor);
  }

  /**

      assertEquals(Service.State.STOPPING, state());
      shutdownCalled++;
    }

    @Override
    protected Executor executor() {
      return executor;
    }

    @Override
    public void tearDown() throws Exception {
      executor.shutdown();
    }
  }

    dispatcher.maxRequestsPerHost = 4
    executor.assertJobs("http://a/1", "http://a/2", "http://a/3", "http://a/4")
  }

  @Test
  fun oldJobFinishesNewJobCanRunDifferentHost() {
    dispatcher.maxRequests = 1
    client.newCall(newRequest("http://a/1")).enqueue(callback)
    client.newCall(newRequest("http://b/1")).enqueue(callback)
    executor.finishJob("http://a/1")
    executor.assertJobs("http://b/1")
  }

  @Test