startScreenshotListner method
Implementation
@override
void startScreenshotListner() {
  // TODO: implement startScreenshotListner
  methodChannel.invokeMethod('startListening');
  methodChannel.setMethodCallHandler((call) async {
    if (call.method == 'onScreenshotTaken') {
      ZoScreenshotListnerBroadcaster().broadcastScreenshotTaken();
      // screenShotcallback();
    }
  });
}