A more "MvvmCross" implementation of https://github.com/paulcbetts/ModernHttpClient.

App.cs

public class App : Cirrious.MvvmCross.ViewModels.MvxApplication {
    public override void Initialize() {
        Mvx.LazyConstructAndRegisterSingleton<IHttpClientFactory, DefaultHttpClientFactory>();
        
        RegisterAppStart(new AppStart());
    }
}

DefaultHttpClientFactory.cs

public class DefaultHttpClientFactory : IHttpClientFactory {
    public HttpClient Get() {
        var handler = new HttpClientHandler();

        if (handler.SupportsAutomaticDecompression) {
            handler.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
        }

        return new HttpClient(handler);
    }
}

DroidHttpClientFactory.cs

public class DroidHttpClientFactory : IHttpClientFactory {
    public HttpClient Get() {
        return new HttpClient(new OkHttpNetworkHandler());
    }
}

DroidSetup.cs

public class Setup : MvxAndroidSetup {
    protected override void InitializeLastChance() {
        base.InitializeLastChance();

        Mvx.LazyConstructAndRegisterSingleton<IHttpClientFactory, DroidHttpClientFactory>();
    }
}

IHttpClientFactory.cs

public interface IHttpClientFactory {
    HttpClient Get();
}