}
  }

  /**
   * Implementation of {@link Stream#flatMap} with a primitive spliterator output type.
   *
   * @param <InElementT> the element type of the input spliterator
   * @param <OutElementT> the (boxed) element type of the output spliterators
   * @param <OutConsumerT> the specialized consumer type for the primitive output type
   * @param <OutSpliteratorT> the primitive spliterator type associated with {@code OutElementT}
   */