分割迭代器：
/** * Returns a spliterator for the elements of this stream. * * <p>This is a <a href="package-summary.html#StreamOps">terminal * operation</a>. * * @return the element spliterator for this stream */ Spliterator<T> spliterator(); Java8（6）spliterator及baseStream 源码讲解在公司的学习笔记。
baseStream 源码讲解