There is a lot of activity around async/await. My understanding is that the hard work is nearly done, and what is left is mostly around the final syntax. I think its planned the land in stable with the Rust 2018 edition (https://blog.rust-lang.org/2018/03/12/roadmap.html) or shortly after it.

There is a recent blog series tracking the quite exciting progress being made at the moment (part vi, latest in the series): https://boats.gitlab.io/blog/post/2018-03-20-async-vi/

There is an experimental RFC tracking generators with an initial syntax design: https://github.com/rust-lang/rfcs/blob/master/text/2033-expe...