Description:
------------
When extending the SPL ArrayIterator class and overloading the offsetGet/offsetSet methods, it appears that neither of the overloaded methods are called when accessing the object like an array (ie $myObject['index'])

Reproduce code:
---------------
<?php
class myArray extends ArrayIterator
{

    public function __construct ($array = array ())
    {
        parent::__construct ($array);
    }

    public function offsetGet ($index)
    {
        echo 'offsetGet called';
        return parent::offsetGet ($index);
    }

    public function offsetSet ($index, $newval)
    {
        echo 'offsetSet called';
        return parent::offsetSet ($index, $newval);
    }

}

$myArray = new myArray ();

$myArray->offsetSet ('one', 'one');
echo $myArray->offsetGet ('one');

$myArray['two'] = 'two';
echo $myArray['two'];
?>

Expected result:
----------------
offsetSet called
offsetGet called
one
offsetSet called
offsetGet called
two

Actual result:
--------------
offsetSet called
offsetGet called
one
two