/**
  * @override
  */
 static function start($sessid = null)
 {
     // by default, maintain a session per shell client
     if (is_null($sessid)) {
         $sessid = trim(`whoami`);
         if (isset($_SERVER['SHELL'])) {
             $sessid .= $_SERVER['SHELL'];
         }
         if (isset($_SERVER['SSH_CLIENT'])) {
             $sessid .= '-' . $_SERVER['SSH_CLIENT'];
         }
         $sessid = preg_replace('/\\W/', '-', $sessid);
     }
     return PLUGSession::start($sessid);
 }
 /**
  * Magic wakeup function.
  * When this is executed the session is not fully initialized, 
  * so we will validate the woken session in {@link PLUGSession::start}
  * @internal
  * @return Void
  */
 private function __wakeup()
 {
     self::$Session = $this;
     $tnow = time();
     $this->t_idle = $tnow - $this->t_resume;
     $this->t_resume = $tnow;
 }