private void goBack(object sender, EventArgs e)
        {
            MCPage1 mc1 = new MCPage1();

            MessagingCenter.Send(mc1, "Hello", "Nagarjun");
            Navigation.PopAsync();
        }
        protected override bool OnBackButtonPressed()
        {
            MCPage1 mc1 = new MCPage1();

            MessagingCenter.Send(mc1, "Hello", "Nagarjun");
            Navigation.PopAsync();
            return(base.OnBackButtonPressed());
        }