A sequence of indicies together with the total number. Use `RangeRestriction.ofSeq` to create one from a sequence. This can be implemented by concrete vector/index builders to allow further optimizations (e.g. when the underlying source directly supports range operations). For example, if your source has an optimised way for getting every 10th address, you can create your own `IRangeRestriction` and then check for it in `LookupRange` and use optimised implementation rather than actually iterating over the sequence of indices.