Description:
------------
when you unset the array which you are iterating. array inconsistent will be 
reported.

I am looking into it, but sadly it is a little difficult to be fixed. since we 
also allow change the item in the iterator function.

thanks

Test script:
---------------
<?php
$arr = array(
    range(1, 10),
    range(1, 10),
    range(1, 10),
    range(1, 10),
    range(1, 10),
);

array_walk_recursive($arr,
    function (&$value, $key) use(&$arr) {
        unset($arr[$key]);
    });

Expected result:
----------------
nothing wrong

Actual result:
--------------
Zend/zend_hash.c(1085) : ht=0x25f5b78 is inconsistent