<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=357404) </details> <!--IssueSummary end--> According to https://gitlab.com/gitlab-org/gitlab/-/merge_requests/83849#note_896168862 not every `realtime_changes_import_${import_type}` endpoint is registered within ETag router. This is definitely ~"bug::performance" for us We need to address this is in one of the following ways: * confirm that this is weird, yet expected * add all `realtime_changes` import endpoints to ETag router * refactor to use one `realtime_changes` endpoint (within new `import/history_controller` which makes sense, since `realtime_changes` are part of the history) instead of having one endpoint per importer (all endpoints are ATM using same logic, specified in `import/base_controller.rb` * or even move all logic to GraphQL Subscriptions, which is doable and acceptable path for now