Why is `fs::Dir` not `Sync`?

[nrath-js]

I was surprised to see that the fs::Dir type is not marked as Sync.

As far as I can tell, all methods that access the internal state require a &mut self, so I think it's fine to use this type from multiple threads without the need for another mutex (since at most one thread can hold a &mut reference).

Am I missing something?

[sunfishcode]

I think you're right; it could be Sync.

[notgull]

It is Sync on the linux_raw backend, but not the libc one.