My low-level actor crate Stakker was first released more than a year ago, but I never properly announced it. So I've written a blog post to introduce it and to highlight some of the design aspects that affect all Rust actor crates:
I posted this on Reddit /r/rust earlier but I know not everyone follows there. There is also a Stakker guide linked from the blog that goes into a lot more detail.
I'm happy to discuss actor system design tradeoffs here. The various actor crates out there seem to have each taken a slightly different angle on this, aiming for different niches.