**BUG REPORT** 1. Please describe the issue you observed: - What did you do (The steps to reproduce)? send transaction messages by producer - What did you expect to see? if the local executor returns an unknown state, the local checker should be called period later. - What did you see instead? 2. Please tell us about your environment: - What is your OS? macOS - What is your client version? 2.0.0 - What is your RocketMQ version? 4.6.1 3. Other information (e.g. detailed explanation, logs, related issues, suggestions on how to fix, etc):