Version 1.39.0 of the Rust language is available. The biggest new feature appears to be the async/await mechanism, which is described in this blog post: "So, what is async await? Async-await is a way to write functions that can 'pause', return control to the runtime, and then pick up from where they left off. Typically those pauses are to wait for I/O, but there can be any number of uses."