HarmonyOS 如何监听蓝牙socket断开

手机通过蓝牙socket连接蓝牙设备(api: socket.sppConnect(device.deviceId, sppOption, clientSocket))。通过socket.on订阅请求回调。现在连接的蓝牙设备关机，要如何监听连接断开？我通过try…catch socket.on方法，但是catch中并没有回调异常信息

socketOn(clientNumber: number, callback: Callback<string>) {
  // 订阅读请求事件
  try {
    socket.on('sppRead', clientNumber, (dataBuffer: ArrayBuffer) => {
      console.info('触发订阅读请求回调！');
      this.receivedData(clientNumber, dataBuffer, callback)
    });
  } catch (err) {
    console.error('errCode: ' + (err as BusinessError).code + ', errMessage: ' + (err as BusinessError).message);
  }
}