AppendIterator test case

test.php

<?php

$iterator1 = new \AppendIterator();
$iterator2 = new \AppendIterator();

$events = new \ArrayIterator(['event']);
$iterator1->append($events);
$iterator2->append($events);

// without this foreach, i will not hang
foreach ($iterator2 as $event) {
}

$iterator1->append(new \ArrayIterator());