protected function hash($path)
    {
        if (is_callable($this->hashCallback)) {
            return call_user_func($this->hashCallback, $path);
        }
        $path = (is_file($path) ? dirname($path) : $path) . filemtime($path);
        return sprintf('%x', crc32($path . Reaction::getVersion() . '|' . $this->linkAssets));
    }