Elliot.

Thank you both for the reviews!

notes: doesn't really affect anything; adds some code that is unused at the moment. putting this up so that people can talk about the design and implementation, and critique it....

Reviewers: Please start with reading the document - https://github.com/XRPLF/rippled/blob/4ab195b1d766410b6f8be79ba3c716cb3110afc0/src/ripple/overlay/MessageScheduler.md

@a-noni-mousse what are your latest thoughts on this change?

@a-noni-mousse can you resolve the merge conflicts? Otherwise, this PR may be closed due to inactivity. You can always open a new PR in the future, of course.

@a-noni-mousse if merge conflicts are not resolved, this PR will be closed. But don't lose heart - you can always re-open it or open a new PR with the changes...

Closing due to inactivity. Feel free to open a new PR with this change (rebased on the head of `develop`).

@mDuo13 any thoughts on `jss::hash`?

This is slated for inclusion in 1.12 (not 1.11) unless anyone comments here to request otherwise.

Released in [1.12.0](https://xrpl.org/blog/2023/rippled-1.12.0.html).