What more can we do?

The mediator holds more exciting possibilities than those we've covered here.

The interface IAsynchronous holds the interface IAsynchronous.IServer. When the provider returns this (wrapped in a FacetHandle as always) it allows the server side to handle the method invocation asynchronously. It can then explicitly call an IAsynchronous.IListener method which is picked up by the client.

Also, thread reuse can be managed much in a much more fine-grained way than just setting a true/false flag.

We won't cover either of these things here, but have a look at the Javadoc for details. Everything can be found in org.jtrix.base.