windows_registry::Key should be Send

[talagrand]

Suggestion

It just wraps an HKEY, so it should be safe to move between threads.

[riverar]

There's a documented bug from the 90s on race conditions with concurrent access (https://helparchive.huntertur.net/document/37759). Doesn't appear to be an issue today but Microsoft doesn't document it as thread-safe, so not sure it's safe to assert this.

[talagrand]

There's two things:

1. Is a reg key handle safe to move between threads, which is denoted by "Send". This doesn't expose the key to any concurrent access, hence the suggestion.

2. Is a reg key handle safe to use concurrently. This is more challenging. Enumerating a key while it's being modified concurrently is not great news. Rust's type system is of limited utility here because you can just open a second handle to the same node to perform concurrent access. Concurrency questions are more about the backing resource than the handle itself (as in the issue you linked to)
   It may be worth annotating the enumeration APIs as taking &mut but it's unclear how much value there is there.

So for now I'd just suggest addressing the first.