private async void Cancel_ClickedAsync(object sender, EventArgs e) //Mostra il form di registrazione
        {
            await RegisterStack.FadeTo(0, 500);

            await RegisterStack.TranslateTo(0, 1000, 1);

            await LoginStack.TranslateTo(0, 0, 1);

            await LoginStack.FadeTo(1, 500);
        }
        private async void LoginFade()
        {
            await RegisterStack.FadeTo(0, 1);

            await RegisterStack.TranslateTo(0, 1000, 1);
        }