Broker in asp.net core NET6

[Navorski]

In the examples there is a Server_ASP_NET_Samples, there is a Startup sealed class, with
Configure(IApplicationBuilder app, IWebHostEnvironment environment, MqttController mqttController)

But how exactly is this to be approached in NET6? since the startup.cs doesnt have the MqttController, and also the MqttConnectionHandler is sealed, so not accessible from the Startup.cs file?

I don't seem to get a server/broker running next to my Web application.

Are there any running examples/solutions available for .NETCore with MQTTnet 4?

Br,
Lander