What would you like to be added/modified:

To improve project stability, we need more tests to cover corner cases.
And the code coverage is around 50% currently, we need to add more tests to improve it.

To improve case coverage, we may need a list of cases to track the work.
For code coverage, simply check bef

Environment

• VerneMQ Version: 1.11.0
• OS: CentOS 8.0
• Erlang/OTP version (if building from source):
• VerneMQ configuration (vernemq.conf) or the changes from the default :
  listener.ssl.default = 0.0.0.0:8883
  listener.ssl.allowed_protocol_versions = 3,4,5
  listener.ssl.require_certificate = on
  mqtt_connect_timeout = 30000
• Cluster size/standalone:

Expected behaviour

Set