I have been reading through the getting started guide and I think I understand how the two message models work.
However, I had a quick question about the services. It sounds like topics are mapped to a service. Topics define the "methods" that are exposed by the service. So, my question is, what happens if I start two instances of the same service? When someone sends a message, does it go to both services and then get two responses? Does the last service started win, making the other service non-functional?