private void Switch_Toggled(object sender, ToggledEventArgs e)
 {
     Model.GroceryItem item = (sender as Switch).Parent.BindingContext as Model.GroceryItem;
     if (item != null)
     {
         Task.Run(async() => await Model.ModelExtensions.PostItemToCollection <Model.GroceryItem>(groceryItemsListView, "shopping", item));
     }
 }
        public GroceryListPage()
        {
            InitializeComponent();

            Command cmd = new Command(() =>
            {
                string id = System.Guid.NewGuid().ToString();
                Model.GroceryItem item = new Model.GroceryItem()
                {
                    _id     = id,
                    what    = groceryItem.Text,
                    ownerId = "jac"
                };

                Task.Run(async() => await Model.ModelExtensions.AddItemAndGetListItemsFromCollection <Model.GroceryItem>(groceryItemsListView, "shopping", item, true));
            });

            AddItem.Command = cmd;
        }