/// <summary>
/// Clears all shopping cart items
/// </summary>
/// <param name="response">HTTP response to save the shopping cart items cookie to</param>
/// <param name="customerUsername">Username of the cookie owner</param>
public static void ClearAllShoppingCartItems(this HttpResponseBase response, string customerUsername)
{
// Saving null collection will cause shopping cart items cookie clearing
response.SaveAllShoppingCartItems(customerUsername);
}