return () -> value;
  }

  /**
   * Creates an {@link AsyncCallable} from a {@link Callable}.
   *
   * <p>The {@link AsyncCallable} returns the {@link ListenableFuture} resulting from {@link
   * ListeningExecutorService#submit(Callable)}.
   *
   * @since 20.0
   */
  @J2ktIncompatible
  @GwtIncompatible
  public static <T extends @Nullable Object> AsyncCallable<T> asAsyncCallable(

          @Override
          public String call() throws Exception {
            return expected;
          }
        };

    AsyncCallable<String> asyncCallable =
        Callables.asAsyncCallable(callable, newDirectExecutorService());

    ListenableFuture<String> future = asyncCallable.call();
    assertSame(expected, future.get());
  }

  @J2ktIncompatible
  @GwtIncompatible

    return () -> value;
  }

  /**
   * Creates an {@link AsyncCallable} from a {@link Callable}.
   *
   * <p>The {@link AsyncCallable} returns the {@link ListenableFuture} resulting from {@link
   * ListeningExecutorService#submit(Callable)}.
   *
   * @since 20.0
   */
  @J2ktIncompatible
  @GwtIncompatible
  public static <T extends @Nullable Object> AsyncCallable<T> asAsyncCallable(