What are you thinking?

I could have used a Mutex then cast the `&Mutex` to `&mut Mutex` so that I could call `.get_mut()`. But this didn't seem simpler.

I wanted to avoid unsafe.

Because unsafe introduces conceptual complications and it seemed to be simpler to avoid that in an example.

Well you can't have a memory race without unsafe. The goal of the example was to show undefined behaviour.

Ah, you wanted to show an example in Rust with unsafe where atomicity was not guaranteed.