This PR #433 changed the signature of Conn's Close method to add an error to the return value. This is a breaking API change that should not have been made in a patch release.

We use this in some of our services at GitHub, and it makes confusing error messages and extra work for us when a patch version update of a dependency suddenly causes compiler errors.

It's not super hard to adjust callers to the new signature, but I hope the authors of this library will be more careful about such changes in the future. API signatures should not be changed willy-nilly.