ShoppingCartController.cs

public async Task<IActionResult> AddToCart(int id, CancellationToken requestAborted)
{
    var cartId = ShoppingCart.GetCartId(HttpContext);
    var cmd = new AddToCart(cartId, id);
    await _mediator.SendAsync(cmd, requestAborted);

    // Go back to the main store page for more shopping
    return RedirectToAction("Index");
}