Interface OuterIterator

`extends`	`Iterator`

OuterIterator extends Iterator
- IteratorIterator implements OuterIterator
  - Salient\Iterator\IterableIterator implements FluentIteratorInterface<TKey, TValue> uses FluentIteratorTrait
  - Salient\Iterator\RecursiveCallbackIterator implements RecursiveIterator<TKey, TValue>
  - Salient\Iterator\MapIterator
  - FilterIterator
    - CallbackFilterIterator
      - RecursiveCallbackFilterIterator implements RecursiveIterator
- RecursiveIteratorIterator implements OuterIterator

Methods
`public`	`getInnerIterator(): Iterator\|null` Implemented by `IteratorIterator::getInnerIterator()` `RecursiveIteratorIterator::getInnerIterator()`	#

Methods inherited from Iterator
`current(), next(), key(), valid(), rewind()`