Thanks for the kind words 
We're actively working on seeing what we can do to get rid of the source generation step -- you can assume this bit might change quite a bit.
We wanted to get the pitch out there so we can begin gathering feedback, I'm pretty hopeful we can get rid of the source-gen step eventually with enough sneaky tricks and thunks.
In general the tricky parts are:
- we got some bytes, we managed to lookup the actor, we even managed to decode the "message" (assuming we have some known representation for it), but how do we apply this message.
- so we need some "function handle that can be looked up from some serializable id and invoked"
- and how do we do this without forcing Codable and some specific representation
- the generation of messages, we would not want to "lock in" forever a specific message representation, say "all funcs have a case in a huge enum" since it may hit limitations or problems for specific transports or just in future evolution of the feature.
- so we need message reprs to be opaque if we were to synthesize them
The good news is that we have some ideas for both of those problems. They would affect the design a bit of course and we'll post a bigger update once we have something to share.
In the meantime it is useful to keep providing feedback about the general feature, thanks in advance!