(PHP 5 >= 5.5.0, PHP 7) Add/insert a new value at the specified index

(PHP 5 >= 5.1.0, PHP 7) Forward to the next element

(PHP 5 >= 5.2.0, PHP 7) User defined sort

(PHP 5 >= 5.1.0, PHP 7) Validates the iterator

(PHP 5 >= 5.3.0, PHP 7) Removes an object from the storage

(PHP 5 >= 5.0.0, PHP 7) Return current array entry

(PHP 5 >= 5.3.0, PHP 7) Return current node index

(PHP 5 >= 5.3.0, PHP 7) Return current node pointed by the iterator

(PHP 5 >= 5.3.0, PHP 7) Returns a PHP array from the fixed array

(PHP 5 >= 5.3.0, PHP 7) Constructs a new empty heap