public async void CallMyService()
        {
            ServiceWrapper serviceWrapper = new ServiceWrapper();
            var model = new UserModel { Username = "******", Password = "******" };

            var result = await serviceWrapper.GetData("test");
            txtMessages.Text = "get call says: " + result;

            result = await serviceWrapper.RegisterUserJsonRequest(model);
            txtMessages.Text = "json post call says: " + result;

            result = await serviceWrapper.RegisterUserFormRequest(model);
            txtMessages.Text = "form post request says: " + result;
        }
        protected async override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource
            Button button = FindViewById<Button>(Resource.Id.MyButton);


            ServiceWrapper serviceWrapper = new ServiceWrapper();
            var model = new UserModel { Username = "******", Password = "******" }; 

            var result = await serviceWrapper.GetData("test");
            button.Text = "get call says: " + result;            

            result = await serviceWrapper.RegisterUserJsonRequest(model);
            button.Text = "json post call says: " + result;

            result = await serviceWrapper.RegisterUserFormRequest(model);
            button.Text = "form post request says: " + result;
        }