*/
  @J2ktIncompatible
  @GwtIncompatible // java.util.concurrent.ScheduledExecutorService
  @IgnoreJRERequirement // Users will use this only if they're already using Duration.
  // TODO(cpovirk): Return ListenableScheduledFuture?
  public static <O extends @Nullable Object> ListenableFuture<O> scheduleAsync(
      AsyncCallable<O> callable, Duration delay, ScheduledExecutorService executorService) {