static function setExpire($time, $add = false)
 {
     if ($add) {
         if (!isset($_SESSION['__HTTP_Session_Expire_TS'])) {
             $_SESSION['__HTTP_Session_Expire_TS'] = time() + $time;
         }
         // update session.gc_maxlifetime
         $currentGcMaxLifetime = Session::setGcMaxLifetime(null);
         Session::setGcMaxLifetime($currentGcMaxLifetime + $time);
     } elseif (!isset($_SESSION['__HTTP_Session_Expire_TS'])) {
         $_SESSION['__HTTP_Session_Expire_TS'] = $time;
     }
 }