Druid project has a policy of creating issues on Github instead of TODOs in code, but I feel that this is an overkill for small documentation-only tasks. I suggest to allow TODOs that ask just for writing or rewriting some text (including internal Javadoc documentation), but not development of any logic, code experiments, benchmarking, etc.
The question is arisen here: https://github.com/apache/incubator-druid/pull/6370#discussion_r219694721
