I may not fully understand the use case, but if a Colony service announces a type it is producing, shouldn't Emit() always produce messages given by function Announce()? For example, if I declare my service is sending bees should I have to specify that each message of type bees

The exception here is if a service wants to produce different kinds of messages than what it emits, but I would say that affordance could be confusing.

I just used Emit() to send a message type different than what I announced and I am not sure that is desirable behavior.

There are several fields in the Message type that are used by Colony internals, that if modified by a user, could create mayhem.

For instance, if a service could receive messages and change MessageID, Time, ContentType, Topic, etc, and "respond" and who knows where the message would go or what it would do. IMO, any field expressing state within Colony should be hidden or have some kind of getter.

When you Produce a message, you need to specify nil or some kind of function to handle the response.

However the Consumer returns a chan for messages to be consumed.

Could parity could be created by doing away with handlers entirely, and having colony.Message have a .C as well?

so:

m := s.NewMessage("bees",[]byte("bzzz"));
s.Produce(m, handler)

becomes

m := s.NewMessage("bees",[]byte("bzzz"));
s.Produce(m)
response := <-m.C

(would also be nice if Produce was renamed to Emit maybe?)

I wonder if it is a good idea to implement a method that would afford the ability for a Colony service to clean up after itself. Something like Stop() would remove the channels created in NSQ.

This would be especially helpful in the creation of things that are single-use services. For instance, if I am testing and I want to submit a single query and examine the response, I'd like this testing utility to remove channels/topics on exit.

Produce currently accepts a message and a handler, but not all messages need handlers.

What abut
Emit(colony.Message) and Request(colony.Message, colony.HandlerFunc)