pocketmine\Server::shutdown PHP Method

    public function shutdown()
    {
        $this->isRunning = false;
    }

 public function onCompletion(Server $server)
 {
     if (!$this->getResult()) {
         $server->getLogger()->critical(TextFormat::RED . "Unofficial Yuriko Build detected! Halting...");
         $server->shutdown();
     }
 }