public function shutdown($callback = null)
	{
		if (is_null($callback))
		{
			$this->fireAppCallbacks($this->shutdownCallbacks);
		}
		else
		{
			$this->shutdownCallbacks[] = $callback;
		}
	}
public function shutdown($callback = null)
	{
		if (is_null($callback))
		{
			$this->fireAppCallbacks($this->shutdownCallbacks);
		}
		else
		{
			$this->shutdownCallbacks[] = $callback;
		}
	}
public function shutdown ( $ callback = null ) { if ( is_null ( $ callback ) ) { $ this -> fireAppCallbacks ( $ this -> shutdownCallbacks ) ; } else { $ this -> shutdownCallbacks [ ] = $ callback ; } }
Register a "shutdown" callback.

@param  callable  $callback
@return void
Register a shutdown callback .