Kameo does have a `spawn_in_thread` function for CPU bound actors if needed.
Right. It's not a very widespread use case, to be honest. You'd find that most would be N actors for M threads (where N <= M ; an Actor in itself is never shared among multiple threads [So `Send` and not `Sync`, in theory] - an inner message handler _could_ have parallel processing but that's up to the user)
I think you should assume in Kameo that every Actor's message handler is going to be CPU-bound. For example, it means that your internal message dispatch and Actor management should be on a separate loop from the User's `async fn handle`. I don't know if it's already the case, but it's an important consideration for your design.
Nice library, BTW, I think it checks all the marks and I like your design. I've tried most of them but could not find one that I liked and/or that would not have a fatal design flaw (like async_traits, ...) :)
PS : Multi-threaded tokio runtime should be the default. Nobody wants a single-threaded actor runtime. It should be in capital letters in the readme.
What makes you think that? Having a large number of actors per thread is by far the most important use case. The Actor model is commonly used in communication systems where there are hundreds of thousands of actors per machine (often one for every single user). In this context, Actors are typically extremely lightweight and not CPU-bound. Instead, they mostly focus on network I/O and are often idle, waiting for messages to arrive or be sent.
- 2 actors on 1 thread = OK
- 1 actor on 2 thread = you are probably doing it wrong.
As for the rest, whether or not they are used in communication systems and whether or not they are cpu-bound, consider there are and run the handle on a separate loop from the main message dispatching. Otherwise you _will_ delay messaging if handles don't await.