How to get information about parameters of the onnx model in Windows.AI.MachineLearning？

Question

I tried to view information about the parameters of the model using windows.ai.machinelearning like this:

               var stream= await StorageFile.GetFileFromApplicationUriAsync(new Uri("ms-appx:///Assets/eye.onnx"));
               model = await LearningModel.LoadFromStreamAsync(stream);
               var ct=model.Metadata.Count();

The returned value of "ct" is 0, but the model can run normally!I changed my code like this：

           int ct = 0;
           foreach (var i in model.Metadata)
           { ct ++; }

The "ct" is still 0，why？