Plugin.AudioRecorder | Audio Recorder plugin for Xamarin and Windows | Form library

I am trying to implement audio streaming from my Xamarin.Forms app to my backend (.net core 2.2). Then my backend will call the Azure cognitive API to transcribe the voice in the audio and return back a string with the transcribed text.

The transcription has to be done and shown in a text box component while the user is speaking (not when he finishes speaking).

To record the audio and put it in a stream I am using the Plugin.AudioRecorder from Nate Rickard (https://github.com/NateRickard/Plugin.AudioRecorder) and it works well. Basicly, it fills a stream with the audio while the user is speaking and saves it to a file.

Nate Rickard also has another plugin using the Azure cognitive service SpeechToText (https://github.com/NateRickard/Xamarin.Cognitive.Speech). This one uses the Plugin.AudioRecorder to capture the voice and then an HttpClient to request the transcription to Azure, getting the text as response. This solution does all the work in the Xamarin.Forms app and I would like the following:

• 1. Send the request stream to my backend instead of directly send it to Azure.
• 1. From my backend send the request to Azure.
• 1. Obtain the Azure response and send it back to my Xamarin.Forms app.

The 2nd and 3rd steps are identical as implemented in the Xamarin.Cognitive.Speech plugin. I am stuck in the first step when I have to handle the http request in my backend. Sending a HttpRequestMessage with a PushStreamContent in it as implemented in Xamarin.Cognitive.Speech plugin, I have changed the URL to send it to my backend instead of send it to azure.

When I run the app I get a 415 status code (Unsuported Media Type error).

Here is the sample code of how the PushStreamContent is built (code from Xamarin.Cognitive.Speech plugin):