Request::getETags PHP Method

        public static function getETags()
        {
            //Method inherited from \Symfony\Component\HttpFoundation\Request
            return \Illuminate\Http\Request::getETags();
        }

 /**
  * Returns whether the entity tags sent with the request match that
  * given by the response.
  *
  * @return bool
  */
 protected function matchEntityTags()
 {
     if ($responding = $this->response->getHeader("ETag")) {
         $requested = $this->request->getETags();
         return $requested && (in_array($responding, $requested) || in_array("*", $requested));
     }
     return false;
 }