ListenableFuture<V> delegate,
      long time,
      TimeUnit unit,
      ScheduledExecutorService scheduledExecutor) {
    if (delegate.isDone()) {
      return delegate;
    }
    return TimeoutFuture.create(delegate, time, unit, scheduledExecutor);
  }

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