*
   * <p>Cancelling a delegate future propagates to input futures once all the delegates complete,
   * either from cancellation or because an input future has completed. If N futures are passed in,
   * and M delegates are cancelled, the remaining M input futures will be cancelled once N - M of
   * the input futures complete. If all the delegates are cancelled, all the input futures will be

    SettableFuture<Object> future1 = SettableFuture.create();
    SettableFuture<Object> future2 = SettableFuture.create();
    SettableFuture<Object> future3 = SettableFuture.create();
    ListenableFuture<List<Object>> all = allAsList(future1, future2, future3);

    future1.setException(new MyException());
    future2.setException(new MyException());
    future3.setException(new MyException());

    try {

    SettableFuture<Object> future1 = SettableFuture.create();
    SettableFuture<Object> future2 = SettableFuture.create();
    SettableFuture<Object> future3 = SettableFuture.create();
    ListenableFuture<List<Object>> all = allAsList(future1, future2, future3);

    future1.setException(new MyException());
    future2.setException(new MyException());
    future3.setException(new MyException());

    try {

    private final ListenableFuture<@Nullable Void> future;
    private boolean called = false;

    private TestCallable(ListenableFuture<@Nullable Void> future) {
      this.future = future;
    }

    @Override
    public ListenableFuture<@Nullable Void> call() throws Exception {
      called = true;
      return future;
    }
  }

    private final ListenableFuture<@Nullable Void> future;
    private boolean called = false;

    private TestCallable(ListenableFuture<@Nullable Void> future) {
      this.future = future;
    }

    @Override
    public ListenableFuture<@Nullable Void> call() throws Exception {
      called = true;
      return future;
    }
  }

    }

    private final ClosingFuture<V1> future1;
    private final ClosingFuture<V2> future2;
    private final ClosingFuture<V3> future3;

    private Combiner3(
        ClosingFuture<V1> future1, ClosingFuture<V2> future2, ClosingFuture<V3> future3) {
      super(true, ImmutableList.of(future1, future2, future3));
      this.future1 = future1;
      this.future2 = future2;
      this.future3 = future3;
    }

 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * <pre>{@code
 * final String name = ...;
 * inFlight.add(name);
 * ListenableFuture<Result> future = service.query(name);
 * future.addListener(new Runnable() {
 *   public void run() {

  protected final void afterDone() {
    super.afterDone();

    ImmutableCollection<? extends Future<?>> localFutures = futures;
    releaseResources(OUTPUT_FUTURE_DONE); // nulls out `futures`

    if (isCancelled() & localFutures != null) {
      boolean wasInterrupted = wasInterrupted();
      for (Future<?> future : localFutures) {
        future.cancel(wasInterrupted);
      }
    }
    /*

      List<Future<String>> futures = testExecutor.invokeAll(tasks);
      mock.assertLastMethodCalled("invokeAll");
      checkResults(futures);
    }
    {
      MockExecutor mock = new MockExecutor();
      TimeUnit unit = TimeUnit.SECONDS;
      long timeout = 5;
      TestExecutor testExecutor = new TestExecutor(mock);
      List<Future<String>> futures = testExecutor.invokeAll(tasks, timeout, unit);

  @CanIgnoreReturnValue
  @ParametricNullness
  static <V extends @Nullable Object, X extends Exception> V getChecked(
      Future<V> future, Class<X> exceptionClass) throws X {
    return getChecked(bestGetCheckedTypeValidator(), future, exceptionClass);
  }

  /** Implementation of {@link Futures#getChecked(Future, Class)}. */
  @CanIgnoreReturnValue
  @VisibleForTesting
  @ParametricNullness