It provides a distributed actor runtime a la Erlang, but for Rust.

The Getting Started example gives some useful insights:

https://github.com/bastion-rs/bastion/blob/master/bastion/ex...

It's a library in rust for actor-model programming like erlang does.

So did it. I didn't know if it was a service or a library or if it integrates with something. Looks like it's a library for Rust. I think mentioning Rust would speed up the understanding of where this sits

It’s more like Nats.io - an async message server, just for rust

Looks like Akka Cluster for rust?