🧐 Motivation

While implementing WithdrawalQueue using Checkpoint, I discovered that the current Checkpoint implementation only allows retrieving values based on specific keys. Since I'm implementing a system that can process requests in ranges by adjusting the offset, it would be beneficial to have a way to retrieve Checkpoint indices or positions.

📝 Details

Target functions: _upperBinaryLookup, _lowerBinaryLookup

1. Add wrapper functions for those functions