Consider adding .try_enumerate() to mirror .enumerate() for Stream<Item = Result<...>>

[v3xro]

.enumerate() is a very convenient way to get a running count of stream results. When trying to use it on a stream that could error, you lose the ability to use functions like .map_ok because the resulting item type is now a tuple (usize, Result<...>). The API loses a little bit of fluency because you have to drop down to a .map call and handle all the cases manually. It would be nice to have a try_enumerate function that would return a Result<(usize, T), Error>.

I apologise if this is not the right place to ask for such a small API change.