public async Task WatchPositionResponse(Position position)
 {
     GeolocationSensorService.NotifyPositionResponse(position);
     await OnValue.InvokeAsync(position);
 }
 public async Task WatchPositionError(PositionError error)
 {
     GeolocationSensorService.NotifyPositionError(error);
     await OnError.InvokeAsync(error);
 }