The source code on master branch can't pass unit test

How to reproduce the error:    just run "mvn clean install -DskipITs" on the latest code Error message:org.apache.rocketmq.remoting.exception.RemotingSendRequestException:  send request to  failed  at 

Re：[GSOC|ROCKETMQ-124] Support non-redundant message delivery mechanism

Hi, Sohaib No message got lost has a higher priority in RocketMQ, so there are some  “waiting for response” or “retry” logic. In consequence there is the “redundant  message” problem.  I think you’d better point out the “redundant message” parts in the current  architecture and describe your