*     input's failure (if not)
   */
  public final <T extends @Nullable Object> FluentFuture<T> transformAsync(
      AsyncFunction<? super V, T> function, Executor executor) {
    return (FluentFuture<T>) Futures.transformAsync(this, function, executor);
  }

  /**
   * Returns a new {@code Future} whose result is derived from the result of this {@code Future}. If