Feature request: please add System Proxy use feature for iOS in Xamarin Forms

While developing an app and hosting the REST API on my own machine images were not shown and the http request were not visible in Fiddler on iOS.

I tracked down this to the IPlatformServices.GetStreamAsync call where you're initiating the CFNetworkHandler without the UseSystemProxy=true parameter.

As of this related bug: https://bugzilla.xamarin.com/show_bug.cgi?id=19135 it is needed to honor the system proxy settings.

Please add in the next build or make a dependency on ModernHttpClient so we will be able to use our own settings and expose a HttpClientFactory of ours for our applications.

Thanks,
Attila