// TODO(cpovirk): Return ListenableScheduledFuture?
  public static <O extends @Nullable Object> ListenableFuture<O> scheduleAsync(
      AsyncCallable<O> callable, Duration delay, ScheduledExecutorService executorService) {
    return scheduleAsync(callable, toNanosSaturated(delay), TimeUnit.NANOSECONDS, executorService);
  }

  /**