proto: Leverage `BTreeMap::extract_if` in `RangeSet` for better performance

[Ralith]

BTreeMap::extract_if was stabilized in Rust 1.91. It could be used to avoid repeatedly traversing the BTreeMap from the root in insert and perhaps elsewhere.

[Perelyn-sama]

I'll make a PR if no one is working on this

[Ralith]

That would be great, thanks! Note 1.91 isn't actually out for another few days, so it won't work in stable rust quite yet and there may be an MSRV concern here -- but this code is very stable so I'm not too worried about merge conflicts if we have to shuffle the change around.

[Perelyn-sama]

1.91 is out now, I'll make a PR within the week. Also, i think it'll be more efficient to use extract_if in the remove method since other methods depend on it. what do you think?

[Ralith]

I expect it's probably beneficial anywhere that it can be used without unreasonable contortions; insert was just an example.

[DSharifi]

Hey @Ralith , I created a PR #2474 that implements this.

I see one issue with this PR, which is increasing the msrv to 1.91 if we want to use BtreeMap::extract_if. Is this something we want to do?

[djc]

I definitely think it's too early to bump the MSRV to 1.91, but I think we discussed whether this could be an opt-in feature?

[DSharifi]

Otherwise, can we just leave the PR open until msrv is bumpted to 1.91 or greater?

[djc]

That's definitely an option.