What is the relationship of com.wowza.wms.stream.publish.Stream and com.wowza.wms.stream.IMediaStream exactly?

What I'd like to do is getting a reference of the com.wowza.wms.stream.publish.Stream instances in my module. These Streams are created similarly to how ServerListenerStreamPublisher works, basically via Stream.createInstance(appInstance, streamName), and then thrown into the application. This happens in a 3rd party module. In my module, running in the same application, I'd like to get hold of these streams and read the playlists, as well as add extra instances of IStreamActionNotify to them

My problem is that given I have an applicationInstance, I am not able to navigate to these objects. There is the appInstance.getMediaCasterStreams(), but that is something different. There is also the getStreams() which returns a MediaStreamMap, but that is also something different.

The API documentation is not helpful, and I don't quite understand the concept. Can you please briefly explain the difference between the above mentioned things and show me a way to access the thing I need?