How can I inspect my Xamarin.Forms app's network traffic?

I have an async method that calls a web service thus (I've omitted some boilerplate stuff):

var client = new HttpClient(new NativeMessageHandler());
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));  
var response = await client.SendAsync(httpRequest);
var jsonString = await response.Content.ReadAsStringAsync();

I know the client.SendAsync() call is successfully connecting to my service, but the requests aren't being picked up by Fiddler.

I want to inspect the request and response headers but Fiddler isn't recording any traffic from my app. I'm using Genymotion emulation, and I've configured the emulator to use the Fiddler proxy (https://cloud.genymotion.com/page/faq/#android-proxy) successfully. If I use the emulator browser to browse the web, the requests appear in the traffic list, yet none of my app's traffic does.

Does anyone have any insight regarding this?

Thanks!
Gabe