rust private

Thread local try with https://github.com/rust-lang/rfcs/pull/2030 was turned into this PR (the RFC was closed, but it looks like just a PR should be good). See also: state stabilization issue: #27716 `try_with` is used in two places in std: stdio and thread_info. In stdio, it would be better if the result was passed to the closure, but in thread_info, it's better as is where the result is returned from the function call. I'm not sure which is better, but I prefer the current way as it better represents the scope.