private async Task StopCameraPreview()
        {
            // Stop the camera preview
            if (Camera != null)
            {
                await Camera.StopPreview();

                Camera = null;
            }
        }
 private async Task StartCameraPreview()
 {
     // Load the camera preview
     Camera = UniversalCamera.GetDefault();
     await Camera.InitPreview(CameraPreview);
 }