(PHP 5 >= 5.1.0, PHP 7) Moves to the next element
(PHP 5 >= 5.1.0, PHP 7) Gets the ArrayIterator
(PHP 5 >= 5.1.0, PHP 7) Gets the current key
(PHP 5 >= 5.1.0, PHP 7) Appends an iterator
(PHP 5 >= 5.1.0, PHP 7) Gets the inner iterator
(PHP 5 >= 5.1.0, PHP 7) Checks validity of the current element
(PHP 5 >= 5.1.0, PHP 7) Gets an index of iterators
(PHP 5 >= 5.1.0, PHP 7) Rewinds the Iterator
(PHP 5 >= 5.1.0, PHP 7) Constructs an AppendIterator
(PHP 5 >= 5.1.0, PHP 7) Gets the current value