/**
   * Returns a {@link LongStream} containing the elements of the first stream, followed by the
   * elements of the second stream, and so on.
   *
   * <p>This is equivalent to {@code Stream.of(streams).flatMapToLong(stream -> stream)}, but the
   * returned stream may perform better.
   *
   * @see LongStream#concat(LongStream, LongStream)
   */
  public static LongStream concat(LongStream... streams) {