public function getETags()
    {
        $result = array();
        if($this->_headers->has('If-None-Match'))
        {
            $result = preg_split('/\s*,\s*/', $this->_headers->get('If-None-Match'), null, PREG_SPLIT_NO_EMPTY);

            //Remove the encoding from the etag
            //
            //RFC-7232 explicitly states that ETags should be content-coding aware
            $result = str_replace('-gzip', '', $result);
        }

        return $result;
    }