Full Pipeline Setup

services.AddMediatR(cfg =>
{
    cfg.RegisterServicesFromAssembly(typeof(MyHandler).Assembly);
    cfg.AddIdempotencyRequestBehavior();
    cfg.AddOpenBehavior(typeof(AppTransactionBehavior<,>));  // subclassed TransactionBehavior
});

services.AddMessaging(builder =>
{
    // 1. Publishing policies (needed by outbox at staging time)
    builder.AddPublishingPolicies(configuration.GetSection("PublishingPolicies"));

    // 2. Outbox (must precede delivery)
    builder.AddOutbox(outbox =>
    {
        outbox.AddOutboxRepository();
        outbox.AddDeliveryIntents();
    });

    // 3. Idempotency backend (before EventBus dispatcher is created)
    builder.AddIdempotencyRedis(opts =>
    {
        opts.Configuration = configuration.GetConnectionString("Redis");
    });

    // 4. Local transport — IMessageService<TContext> + in-process publishers
    builder.AddMessageService<AppDbContext>();    // registers IMessageService<AppDbContext> + local channel
    builder.AddLocalPublisher<AppDbContext>();    // registers LocalTransportPublisher keyed "local"

    // 5. Delivery (creates EventBusBuilder internally — do not call AddEventBus() separately)
    builder.AddDelivery(delivery =>
    {
        // "local" publisher key for durable in-process dispatch
        delivery.AddDeliveryProcessor<AppDbContext>("local",
            "send-pending", "retry-failed", "recover-timeout");
        // "rabbitmq" publisher key for broker dispatch
        delivery.AddDeliveryProcessor<AppDbContext>("rabbitmq",
            "send-pending", "retry-failed", "recover-timeout");
        delivery.AddDeliveryPolicies(configuration.GetSection("DeliveryPolicies"));
    });

    // 5. EventBus with infrastructure
    builder.AddEventBus()
        .AddConsumerServices(consumers =>
        {
            consumers.Subscribe<OrderCreatedEvent, OrderCreatedEventHandler>();
        })
        .AddRabbitMQ(rabbitMQ =>
        {
            // 6. RabbitMQ inside EventBus
            rabbitMQ.AddConnection("rabbitmq", configuration.GetSection("RabbitMQ"))
                    .AddProducer("rabbitmq", "rabbitmq")
                    .AddConsumer("orders", "orders-queue", "rabbitmq");
        });
});

services.AddHealthChecks()
    .AddRabbitMQHealthCheck("rabbitmq", tags: new[] { "ready" })
    .AddOutboxDeliveryHealthCheck<AppDbContext>(opts =>
    {
        opts.StuckMessageThresholdMinutes = 15;
        opts.MaxStuckMessages = 50;
    }, tags: new[] { "live" });