Implement getNearest methods

[matkt]

PR description

Add getNearestAfter method needed for verkle and fix getNearestBefore method

Fixed Issue(s)

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• [ ] Considered documentation and added the doc-change-required label to this PR if updates are required.
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[matkt]

Generally LGTM. the rewrite of getNearest seems a little chat-gpt-y to me though

Thanks for the review.. Can you also tell me what bothers so that I can change. Is factorization too hard to understand ?

The use of Min Max on this case is more interesting because it avoids sorting that would be more expensive. This is why this proposal seems to me more interesting for this call. But I can understand that the overall factorization of the method is complex and I can try to simplify by duplicating more

[matkt]

@garyschulte did some cleanning in the PR, I also modified the tests in order to check more edgcases, the new tests are comparing directly with rocksdb instead of hardcoding the responses

thanks to that I fixed some new issues

[garyschulte]

The use of Min Max on this case is more interesting because it avoids sorting that would be more expensive.

that makes a lot of sense, min/max will be O(n). 👍

[macfarla]

@garyschulte is this GTG?

[matkt]

yes will fix the PR