<Explain the goal of the PR for the implementation to be judged against. Link to relevant context including issues, papers, etc>
<Survey coverage by existing or new tests, create a checklist for uncovered changes. For changes impractical to test, list them and consider a demo for human checking.>
- [ ] Rustdoc and implementation comments? - [ ] Self review comments on non-obvious changes? - [ ] It seems to you ready to merge on master?