public function matchingListeners($eventKeyPattern)
    {
        $matchPattern = '/' . preg_quote($eventKeyPattern, '/') . '/';
        $matches = array_intersect_key(
            $this->_listeners,
            array_flip(
                preg_grep($matchPattern, array_keys($this->_listeners), 0)
            )
        );

        return $matches;
    }