Mo Bitar

I can take care of the CI test later. Probably a Windows issue. We shouldn't use traits / trait bounds because the exercises about them are after the generics exercises....

> i tried to have &[Option] as an argument but it requires T to implement Clone (and i couldn't find any suitable workaround) Oh, yeah. We would need to return...

I don't find this feedback constructive. I will rename the issue to focus on one point.

Now that the async chapter is added to the book, I am open to exercise ideas :)

Tokio for sure. Rustlings v6 allows adding dependencies to exercises, but this possibility is not used in any exercise yet.

You just add the dependency to the [`dev/Cargo.toml`](https://github.com/rust-lang/rustlings/blob/main/dev/Cargo.toml) file.