public function & SetFilter ($handler, $direction = \MvcCore\IRoute::CONFIG_FILTER_IN) {
		// there is possible to call any `callable` as closure function in variable
		// except forms like `'ClassName::methodName'` and `['childClassName', 'parent::methodName']`
		// and `[$childInstance, 'parent::methodName']`.
		$closureCalling = (
			(is_string($handler) && strpos($handler, '::') !== FALSE) ||
			(is_array($handler) && strpos($handler[1], '::') !== FALSE)
		) ? FALSE : TRUE;
		/** @var $this \MvcCore\Route */
		$this->filters[$direction] = [$closureCalling, $handler];
		return $this;
	}