Note breaking change of network interface

[stubailo]

TODO:

• If this PR is a new feature, reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests
• Rebase your changes on master so that they can be merged easily
• Make sure all tests and linter rules pass
• Update CHANGELOG.md with your change
• Add your name and email to the AUTHORS file (optional)
• If this was a change that affects the external API, update the docs and post a link to the PR in the discussion

[stubailo]

@helfer do we actually want to make this change? It doesn't seem to really improve much, just seems like a breaking change for the sake of it. Perhaps we can keep backcompat and print a warning, then remove it in 1.0?

[helfer]

@stubailo I made the change because there was a comment in the code that said we were just doing that for backcompat. I think now is as good a time as any to make that breaking change, but I'm not dead set on it, if you want to undo it.

[stubailo]

I guess we never documented the new way and it's really easy to not break it - so maybe let's put it back?

[stubailo]

Closing in favor of #828