Consumer.cs

public class CustomerOrderEventNotificationHandler : ICapSubscribe
{
    private readonly IHubContext<CustomerOrderHub> _hubContext;

    public CustomerOrderEventNotificationHandler(IHubContext<CustomerOrderHub> hubContext)
    {
        _hubContext = hubContext;
    }

    [CapSubscribe(nameof(OrderBeingPreparedEvent), Group = nameof(CustomerOrderEventNotificationHandler) + ":" + nameof(OrderBeingPreparedEvent))]
    public async Task Handle(OrderBeingPreparedEvent orderBeingPreparedEvent)
    {
        await _hubContext.Clients.Group(orderBeingPreparedEvent.OrderId.ToString()).SendAsync("OrderBeingPrepared");
    }

    [CapSubscribe(nameof(OrderPickedUpForDeliveryEvent), Group = nameof(CustomerOrderEventNotificationHandler) + ":" + nameof(OrderPickedUpForDeliveryEvent))]
    public async Task Handle(OrderPickedUpForDeliveryEvent orderPickedUpForDeliveryEvent)
    {
        await _hubContext.Clients.Group(orderPickedUpForDeliveryEvent.OrderId.ToString()).SendAsync("OrderPickedUpForDelivery");
    }

    [CapSubscribe(nameof(OrderDeliveredEvent), Group = nameof(CustomerOrderEventNotificationHandler) + ":" + nameof(OrderDeliveredEvent))]
    public async Task Handle(OrderDeliveredEvent orderDeliveredEvent)
    {
        await _hubContext.Clients.Group(orderDeliveredEvent.OrderId.ToString()).SendAsync("OrderDelivered");
    }
}