code: static function create(string $app, ?string $listen = null, ?array $ssl = null, bool $businessWorker = true) {
          parent::create($app);
          self::$_apps[$app] = new self($app, $listen, $ssl);
          if ($businessWorker)
              self::$_apps[$app]->addBusinessWorker();
          return self::$_apps[$app];
      }
docs: 创建服务
  
  @param string $app
  @param null|string $listen
  @param array|null $ssl
  @param bool $businessWorker
  @return Server