> Go is focused on concurrency as a first class concept. That is not to say you cannot find aspects of Go’s actor oriented concurrency in Rust, but it is left as an exercise to the programmer.

To be fair, concurrency is baked the Rust type system itself. It's certainly a first class concept. I think the better way to describe it is that Rust wants to make concurrency safe regardless of what mechanism it's based on (system threads, futures/asyncio, maybe other things eventually?), while Go wants to provide a particular (very convenient) mechanism as part of the language.