private static async void ImageUpdateTimerCallback(object state)
{
   DateTime requestAtUtc = DateTime.UtcNow;

   // Just incase - stop code being called while photo already in progress
   if (_cameraBusy)
   {
      return;
   }
   _cameraBusy = true;

   Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Image processing start");

   try
   {
#if SECURITY_CAMERA
      Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Security Camera Image download start");

      using (Stream cameraStream = await _httpClient.GetStreamAsync(_applicationSettings.CameraUrl))
      using (Stream fileStream = File.Create(_applicationSettings.ImageInputFilenameLocal))
      {
         await cameraStream.CopyToAsync(fileStream);
      }

      Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Security Camera Image download done");
#endif

      List<YoloPrediction> predictions;

      // Process the image on local file system
      using (Image<Rgba32> image = await Image.LoadAsync<Rgba32>(_applicationSettings.ImageInputFilenameLocal))
      {
         Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} YoloV5 inferencing start");
         predictions = _scorer.Predict(image);
         Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} YoloV5 inferencing done");

#if OUTPUT_IMAGE_MARKUP
         Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Image markup start");

         var font = new Font(new FontCollection().Add(_applicationSettings.ImageOutputMarkupFontPath), _applicationSettings.ImageOutputMarkupFontSize);

         foreach (var prediction in predictions) // iterate predictions to draw results
         {
            double score = Math.Round(prediction.Score, 2);

            var (x, y) = (prediction.Rectangle.Left - 3, prediction.Rectangle.Top - 23);

            image.Mutate(a => a.DrawPolygon(Pens.Solid(prediction.Label.Color, 1),
                  new PointF(prediction.Rectangle.Left, prediction.Rectangle.Top),
                  new PointF(prediction.Rectangle.Right, prediction.Rectangle.Top),
                  new PointF(prediction.Rectangle.Right, prediction.Rectangle.Bottom),
                  new PointF(prediction.Rectangle.Left, prediction.Rectangle.Bottom)
            ));

            image.Mutate(a => a.DrawText($"{prediction.Label.Name} ({score})",
                  font, prediction.Label.Color, new PointF(x, y)));
         }

         await image.SaveAsJpegAsync(_applicationSettings.ImageOutputFilenameLocal);

         Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Image markup done");
#endif
      }


#if PREDICTION_CLASSES
      Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Image classes start");
      foreach (var prediction in predictions)
      {
         Console.WriteLine($"  Name:{prediction.Label.Name} Score:{prediction.Score:f2} Valid:{prediction.Score > _applicationSettings.PredictionScoreThreshold}");
      }
      Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss:fff} Image classes done");
#endif

#if PREDICTION_CLASSES_OF_INTEREST
      IEnumerable<string> predictionsOfInterest = predictions.Where(p => p.Score > _applicationSettings.PredictionScoreThreshold).Select(c => c.Label.Name).Intersect(_applicationSettings.PredictionLabelsOfInterest, StringComparer.OrdinalIgnoreCase);

      if (predictionsOfInterest.Any())
      {
         Console.WriteLine($" {DateTime.UtcNow:yy-MM-dd HH:mm:ss} Camera image comtains {String.Join(",", predictionsOfInterest)}");
      }

#endif
   }
   catch (Exception ex)
   {
      Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Camera image download, upload or post procesing failed {ex.Message}");
   }
   finally
   {
      _cameraBusy = false;
   }

   TimeSpan duration = DateTime.UtcNow - requestAtUtc;

   Console.WriteLine($"{DateTime.UtcNow:yy-MM-dd HH:mm:ss} Image processing done {duration.TotalSeconds:f2} sec");
   Console.WriteLine();
}

{
   "ApplicationSettings": {
      "ImageTimerDue": "0.00:00:15",
      "ImageTimerPeriod": "0.00:00:30",

      "CameraUrl": "HTTP://10.0.0.56:85/images/snapshot.jpg",
      "CameraUserName": "",
      "CameraUserPassword": "",

      "ImageInputFilenameLocal": "InputLatest.jpg",
      "ImageOutputFilenameLocal": "OutputLatest.jpg",

      "ImageOutputMarkupFontPath": "C:/Windows/Fonts/consola.ttf",
      "ImageOutputMarkupFontSize": 16,

      "YoloV5ModelPath": "YoloV5/yolov5s.onnx",

      "PredictionScoreThreshold": 0.5,

      "PredictionLabelsOfInterest": [
         "bicycle",
         "person",
         "bench"
      ]
   }
}