*
   * <p><b>Warning:</b> If the input future does not already implement {@code ListenableFuture}, the
   * returned future will emulate {@link ListenableFuture#addListener} by taking a thread from an
   * internal, unbounded pool at the first call to {@code addListener} and holding it until the
   * future is {@linkplain Future#isDone() done}.
   *
   * <p>Prefer to create {@code ListenableFuture} instances with {@link SettableFuture}, {@link

 * </ul>
 *
 * <p>The main purpose of {@link #addListener addListener} is to support this chaining. You will
 * rarely use it directly, in part because it does not provide direct access to the {@code Future}
 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * {@snippet :
 * final String name = ...;

    listenable.addListener(earlyListener, directExecutor());

    input.allowGetToComplete.countDown();
    // Now give the get() thread time to finish:
    assertTrue(earlyListener.wasRun.await(1, SECONDS));

    // Now test an additional addListener call, which will be run in-thread:
    RecordingRunnable lateListener = new RecordingRunnable();
    listenable.addListener(lateListener, directExecutor());

      // racing addListener calls and addListener calls completing after the future completes.
      Runnable listener = k % 2 == 0 ? collectResultsRunnable : collectResultsTimedGetRunnable;
      allTasks.add(callable(listener));
      allTasks.add(
          () -> {
            currentFuture.get().addListener(listener, executor);
            return null;
          });
    }

 * </ul>
 *
 * <p>The main purpose of {@link #addListener addListener} is to support this chaining. You will
 * rarely use it directly, in part because it does not provide direct access to the {@code Future}
 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * {@snippet :
 * final String name = ...;

      // racing addListener calls and addListener calls completing after the future completes.
      Runnable listener = k % 2 == 0 ? collectResultsRunnable : collectResultsTimedGetRunnable;
      allTasks.add(callable(listener));
      allTasks.add(
          () -> {
            currentFuture.get().addListener(listener, executor);
            return null;
          });
    }

  protected ForwardingListenableFuture() {}

  @Override
  protected abstract ListenableFuture<? extends V> delegate();

  @Override
  public void addListener(Runnable listener, Executor exec) {
    delegate().addListener(listener, exec);
  }

  // TODO(cpovirk): Use standard Javadoc form for SimpleForwarding* class and constructor
  /**

    }

    @Override
    public final boolean isCancelled() {
      return super.isCancelled();
    }

    @Override
    public final void addListener(Runnable listener, Executor executor) {
      super.addListener(listener, executor);
    }

    @CanIgnoreReturnValue
    @Override
    public final boolean cancel(boolean mayInterruptIfRunning) {

    listenable.addListener(earlyListener, directExecutor());

    input.allowGetToComplete.countDown();
    // Now give the get() thread time to finish:
    assertTrue(earlyListener.wasRun.await(1, SECONDS));

    // Now test an additional addListener call, which will be run in-thread:
    RecordingRunnable lateListener = new RecordingRunnable();
    listenable.addListener(lateListener, directExecutor());

 * FutureTask}, {@code ListenableFutureTask} does not provide an overrideable {@link
 * FutureTask#done() done()} method. For similar functionality, call {@link #addListener}.
 *
 * <p>Few users should use this class. It is intended primarily for those who are implementing an
 * {@code ExecutorService}. Most users should call {@link ListeningExecutorService#submit(Callable)