Please document this method. I have found a use for it and would love to better understand how it works. TY : )
(PHP 5, PHP 7, PHP 8)
RecursiveIteratorIterator::getSubIterator — The current active sub iterator
本函数还未编写文档，仅有参数列表。
level
The current active sub iterator on success; null on failure.
| 版本 | 说明 |
|---|---|
| 8.0.0 |
level is now nullable.
|