We want to add a FailureDetector module on the broker to detect the server failures, and take failed servers out of the routing

Design doc: https://docs.google.com/document/d/1X32OMT6lC4pCveQVzK6OvRlaW0kE9HZ2vn_EHzesM1w/edit?usp=sharing