Creates a Service, which can be passed into a Manager and then used by
others through a Connection.
The T is the service description module. All public methods of T
will be remotely callable. Please see samples/rpc for a usage example.
Remotely callable methods in T, whose last argument, or only argument,
is a Connection, will have the calling Connection injected. The
connection argument "disappears" from the client-side.
A Service can only be registered to a single Manager.