Hm, hm, hm. This is the first I've heard of it, but I have to admit I am often frustrated that std does not have the type, and it's a high-quality bluss crate.

I'm on the fence.

To me it seems like the benefits exceed the costs of adding it. It also feels like the sort of thing that wouldn't go into the standard library any time soon, and that it'd be a hard case to get it in this year.

Still on my radar, but still undecided.