```php
$mutex = $this;
register_shutdown_function(function() use ($mutex) {
    // use $mutex->_items / $mutex->getItems()
});
```
I wonder why this works. I always thought lambdas can access only public class members and it seemed to me absolutely illogical.

```php
$items =& $this->_items;
register_shutdown_function(function() use (&$items) {
    // use $items
});
```
Ok, i think this is the best of all.

```php
register_shutdown_function(function(&$items){
    // use $items
}, &$this->_items);
```
This will cause fatal error: `Call-time pass-by-reference has been removed`.