Update: This issue has been updated to add Cloud Events support to existing EventStore We are going to implement Duo Code Reviews as a sample use case. ``` # ee/app/services/ee/merge_requests/base_service.rb def handle_reviewers_change(merge_request, old_reviewers) super new_reviewers = merge_request.reviewers - old_reviewers request_duo_code_review(merge_request) if new_reviewers.any?(&:duo_code_review_bot?) execute_flow_triggers(merge_request, new_reviewers, :assign_reviewer) end ``` In this code we execute the triggers for Code Review Flow. But the goal is to raise an event for Merge Requests Reviewers Assigned. Adding subscribers will be done in follow up issues.