I'd like to request a spine-rust runtime. I am working with a spine-c transpile and it is fully featured and works, but it is extremely non-ergonomic. Hard to extend support to various engines in the current state.
spine-rust
We currently don't have to resources to build our own idiomatic Rust runtime I'm afraid. There is a 3rd party runtime which seems to be pretty good though:
jabuwu/rusty_spine
Yes, I am a maintainer of that runtime. 
LOL, sorry I didn't notice. I'm afraid what I said still stands though. Rust is simply not a big enough target for us to divert resources to it, I'm sorry :/