public static function clear()
 {
     foreach (SessionStorage::getAll() as $key => $value) {
         if (strpos($key, self::$FLASH_MESSAGE_PREFIX) === 0) {
             SessionStorage::delete($key);
         }
     }
 }
 public function getLoggedInUser()
 {
     return SessionStorage::get(self::$USER_VAR);
 }
 private function setupSession()
 {
     if (Config::useSession()) {
         SessionStorage::initialize();
     }
 }