getDeviceManager method Null safety
获取设备管理模块。
Implementation
TXDeviceManager getDeviceManager() {
  _channel.invokeMethod('getDeviceManager');
  return new TXDeviceManager(_channel);
}获取设备管理模块。
TXDeviceManager getDeviceManager() {
  _channel.invokeMethod('getDeviceManager');
  return new TXDeviceManager(_channel);
}