_onDisconnect(reason) {
    log("info", "Uib:ioSetup:socket-disconnect", "\u26D4 Socket Disconnected. Reason: ".concat(reason))();
    this._dispatchCustomEvent("uibuilder:socket:disconnected", reason);
    this._checkConnect();
  }
Called by _ioSetup when Socket.IO disconnects from Node-RED
@param {string} reason Disconnection title
@private