// so that the cleanup work is visible to listeners.
      // afterDone() should be generally fast and only used for cleanup work... but in theory can
      // also be recursive and create StackOverflowErrors
      future.afterDone();
      // push the current set of listeners onto next
      next = future.clearListeners(next);
      future = null;

    input.addListener(output, rejectionPropagatingExecutor(executor, output));
    return output;
  }

  /*
   * In certain circumstances, this field might theoretically not be visible to an afterDone() call
   * triggered by cancel(). For details, see the comments on the fields of TimeoutFuture.
   */
  @LazyInit @Nullable ListenableFuture<? extends V> inputFuture;
  @LazyInit @Nullable Class<X> exceptionType;

  // this would be observable from an afterDone callback
  public void testListenersExecuteImmediately_fromAfterDone() {
    AbstractFuture<String> f =
        new AbstractFuture<String>() {
          @Override
          protected void afterDone() {
            AtomicBoolean ranImmediately = new AtomicBoolean();