Description:
------------
---
From manual page: http://www.php.net/function.iterator-apply
---
Iteration doesn't work as expected on SplDoublyLinkedList, as if next() was not called while using current() inside the callback passed to iterator_apply

https://3v4l.org/ARLUZ


Test script:
---------------
<?php
$ll = new SplDoublyLinkedList();

$ll->push('one');
$ll->push('two');
$ll->push('three');
$ll->push('four');

$ll->rewind();

$iterations_done = iterator_apply($ll, function(Iterator $it) {
    echo $it->key(),"\t->", $it->current(),"\t->", ucfirst($it->current()),".\n";
    return true;
}, array($ll));
echo "Did iterate {$iterations_done} times \n";

foreach($ll as $key => $value) {
    $uppercase = ucfirst($value);
    echo "{$key}\t->{$value}\t->{$uppercase}.\n";
}

Expected result:
----------------
0	->one	->One.
1	->two	->Two.
2	->three	->Three.
3	->four	->Four.
Did iterate 4 times 
0	->one	->One.
1	->two	->Two.
2	->three	->Three.
3	->four	->Four.

Actual result:
--------------
0	->one	->One.
0	->one	->One.
0	->one	->One.
0	->one	->One.
Did iterate 4 times 
0	->one	->One.
1	->two	->Two.
2	->three	->Three.
3	->four	->Four.