local_addr should not return an Option

[dpc]

I applied your GH suggestion without actually checking, and I think this was your actual intention all along.

[ibraheemdev]

Ah it seems I missed the point of the Option and Result. The None case isn't really an IO error, so merging it into one is a little odd. I'm open to your thoughts on this and don't have a strong preference.

[dpc]

I don't think it matters much one way or another. Barely anyone actually need this call, and if they do, they know they just called bind anyway.

Nested Option<Result<_>> is just not very convenient. Otherwise people can just ? if they want bubble up, or .expect if they want to panic. I think the way it is in this PR is totally fine.

[ibraheemdev]

Sounds good, thanks!