SendSync Occasionally return topic=xxx route info not found err

[wumingzhidewu]

BUG REPORT

1. Please describe the issue you observed:

   • What did you do (The steps to reproduce)?

   producer.SendSync(ctx, m) ,somtime return topic=xxx route info not found err,but this topic i have created

   • What did you expect to see?

     The specific cause of the problem should be returned, and the retry mechanism should take effect. At present, the retry mechanism has no effect

2. Please tell us about your environment:

   • What is your OS?

     centos 7.6

   • What is your client version?

     https://github.com/apache/rocketmq-client-gov2.1.2

   • What is your RocketMQ version?

     RocketMQ4.9