* Executors#newSingleThreadExecutor}).
   *
   * @since 23.3 (since 23.1 as {@code sequentialExecutor})
   */
  @GwtIncompatible
  public static Executor newSequentialExecutor(Executor delegate) {
    return new SequentialExecutor(delegate);
  }

  /**
   * Creates an {@link ExecutorService} whose {@code submit} and {@code invokeAll} methods submit