[ISSUE #8145] Optimize some code style in client module

[Willhow-Gao]

Which Issue(s) This PR Fixes

Fixes #8145

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 61.90476% with 8 lines in your changes are missing coverage. Please review.

Project coverage is 42.91%. Comparing base (03b16aa) to head (21fcf9a).
Report is 1 commits behind head on develop.

Files	Patch %	Lines
...mq/client/impl/producer/DefaultMQProducerImpl.java	57.14%	2 Missing and 4 partials ⚠️
...rocketmq/client/impl/factory/MQClientInstance.java	66.66%	1 Missing ⚠️
...he/rocketmq/client/trace/AsyncTraceDispatcher.java	66.66%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #8146      +/-   ##
=============================================
- Coverage      42.93%   42.91%   -0.03%     
+ Complexity     10386    10377       -9     
=============================================
  Files           1270     1270              
  Lines          88693    88689       -4     
  Branches       11401    11402       +1     
=============================================
- Hits           38083    38060      -23     
- Misses         45920    45931      +11     
- Partials        4690     4698       +8     

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