private async void sign_out(object sender, EventArgs e)
        {
            App.UserUID = "";
            await authSignOut.SignOut();

            App.Current.MainPage = new NavigationPage(new LogIn());
            App.Current.Properties.Remove("App.UserUID");
            await App.Current.SavePropertiesAsync();

            Console.WriteLine("---------------------------------" + App.Current.Properties.Count());
            // back button disabled
            OnBackButtonPressed();
        }
        private async void sign_out(object sender, EventArgs e)
        {
            if (!busyindicator.IsVisible && allowPopup)
            {
                allowPopup  = false;
                App.UserUID = "";
                await authSignOut.SignOut();

                App.Current.MainPage = new NavigationPage(new LogIn());
                App.Current.Properties.Remove("App.UserUID");
                await App.Current.SavePropertiesAsync();

                //Console.WriteLine("---------------------------------" + App.Current.Properties.Count());
                // back button disabled
                OnBackButtonPressed();
                allowPopup = false;
            }
        }