Interface Countable

Countable
- SplDoublyLinkedList implements Iterator, Countable, ArrayAccess, Serializable
  - SplQueue
- SplObjectStorage implements Countable, Iterator, Serializable, ArrayAccess
- League\CommonMark\Reference\ReferenceMapInterface extends IteratorAggregate<ReferenceInterface>, Countable

Methods
`public`	`count(): int` Implemented by `SplDoublyLinkedList::count()` `SplObjectStorage::count()`	#