static public function register( $callBack, $priority = 0 )
	{
		if( !self::$_registered )
		{
			register_shutdown_function( array( __class__, '_registered_shutdown' ) );
			self::$_registered = true;
		}
		$params                                     = func_get_args();
		self::$_registeredCallbacks[ ++self::$_id ] = array( $callBack, (int) $priority, self::$_id,
		                                                     array_slice( $params, 2 )
		);
		return self::$_id;
	}