private async void DeleteContact_Clicked(object sender, EventArgs e)
        {
            var contactItem = (sender as MenuItem).CommandParameter as Contact;

            var result = await DisplayAlert("Warning", string.Format("Are you sure you want to delete {0}", contactItem.FullName), "Yes", "No");

            if (result)
            {
                _contactServices.RemoveContact(contactItem);
            }
        }