feat(kad): report automatic changes to kad mode

[dhuseby]

Description

Previously, the kademlia protocol would only log changes to the internal mode. With this patch, we now also emit an event which allows users to code against the internal state of the kademlia protocol.

Fixes #4310.

Notes & open questions

Added code to emit a ModeChanged event whenever in automatic mode and we detect a mode change from the external addresses the swarm knows about.

Previous broken PRs: #4341 and #4499

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[thomaseizinger]

Thanks @dhuseby !

[mxinden]

Small suggestions, otherwise this looks good to me. Adding it to the v0.53 milestone.

[mergify]

This pull request has merge conflicts. Could you please resolve them @dhuseby? 🙏

[dhuseby]

@mxinden or @thomaseizinger I just resolved the CHANGELOG.md issues and put this in the 0.44.5 version but I think this may be a breaking change; that's why we had it in a 0.45.0 release initially.

[dhuseby]

@thomaseizinger and @mxinden heads up, I bumped kad to 0.45.0 and made the corresponding change to the CHANGELOG.md.

[thomaseizinger]

Thanks! Looking forward to this being included in the next release :)

[mergify]

This pull request has merge conflicts. Could you please resolve them @dhuseby? 🙏

[thomaseizinger]

@dhuseby Can you deal with the CI errors? #4547 renamed some symbols in libp2p-kad.

[dhuseby]

@thomaseizinger the only CI test that fails now is the cargo dependency security check. I think this PR has caught up. Also, what's the process for taking care of the dependencies that need to be updated? Should I post issues for the old deps the CI found? How quickly do we usually address these?

[thomaseizinger]

@thomaseizinger the only CI test that fails now is the cargo dependency security check. I think this PR has caught up. Also, what's the process for taking care of the dependencies that need to be updated? Should I post issues for the old deps the CI found? How quickly do we usually address these?

Thanks! I am not sure where that one slipped in. I'll send a separate PR to fix it.

Approvals have been dismissed because the PR was updated after the send-it label was applied.