private async void ListViewTechnicians_ItemTapped(object sender, ItemTappedEventArgs e)
        {
            //_vm.SignIn(e.Item as Models.JT_Technician);
            //_vm.IsSignedIn = false;
            await Task.Run(() => _vm.SignIn(e.Item as Models.App_Technician));            // puke

            //MainApp.Technician = e.Item as Models.JT_Technician;
            //App.Database.CreateDependentTables(App.CurrentTechnician);

            //MainApp.MoveNext();
        }
 private void Bw_DoWork(object sender, DoWorkEventArgs e)
 {
     Models.App_Technician appTechnician = (Models.App_Technician)e.Argument;
     _vm.SignIn(appTechnician);
 }