Configure.With(new EmptyActivator())
    .Transport(t => t.UseRabbitMqAsOneWayClient(_container.ConnectionString))
    .Serialization(s => s.UseCloudEvents()
        .AddWithCustomName<UserLoggedIn>("io.cloudevents.demo.user.loggedIn") // explicit
        .AddWithShortName<UserLoggedIn>()) // or with short name
    .Start();

Configure.With(activator)
    .Transport(t => t
        .UseNativeHeaders()
        .UseAzureServiceBus($"Endpoint={ConnectionString}", queue, new DefaultAzureCredential()))
    .Options(o => o
        .UseCustomTypeNameForTopicName())
    .Serialization(s => s.UseCloudEvents()
        .AddWithCustomName<UserLoggedIn>("io.cloudevents.demo.user.loggedIn")) // <-- all types _must_ be mapped explicitly, either by short name or custom name
    .Start();

Configure.OneWayClient()
    .Transport(t => t
        .UseNativeHeaders()
        .UseAzureServiceBusAsOneWayClient($"Endpoint={ConnectionString}", new DefaultAzureCredential()))
    .Options(o => o
        .UseSenderAddress("my-custom-source")
        .UseCustomTypeNameForTopicName())
    .Serialization(s => s.UseCloudEvents()
        .AddWithCustomName<UserLoggedIn>("io.cloudevents.demo.user.loggedIn")) // <-- all types _must_ be mapped explicitly, either by short name or custom name
    .Start();

var bus = Bus.Factory
    .CreateUsingRabbitMq(cfg =>
    {
        cfg.UseCloudEvents()
    };

var bus = Bus.Factory
    .CreateUsingRabbitMq(cfg =>
    {
        cfg.ReceiveEndpoint("...", x =>
        {
            x.UseCloudEvents();
        }
    };

.UseCloudEvents()
    .WithTypes(t => t.Map<UserLoggedIn>("loggedIn"));

.UseCloudEvents()
    .WithTypes(t => t.Map<UserLoggedIn>("loggedIn"), map => map with { Subject = x => x.SomeProperty });