HH\Iterator::key
( excerpt from http://php.net/manual/en/iterator.key.php )
public function key(): mixed;
Returns the key of the current element.
Returns
mixed- Returns scalar on success, or NULL on failure.
( excerpt from http://php.net/manual/en/iterator.key.php )
public function key(): mixed;
Returns the key of the current element.
mixed - Returns scalar on success, or NULL on failure.