[improve][broker] Improve SystemTopicBasedTopicPoliciesService reader to reduce GC pressure

[dao-jun]

Motivation

Make the reader referenced by SystemTopicBasedTopicPoliciesService pooling messages to reduce GC pressure.

If poolMessage=false of the Reader, pulsar client will copy message payload into heap without pooling.
Generally, it is not recommended to users use the feature, because it requires call message.release() manually, or it will lead to mem leak.

However, in the broker side, we need this feature to improve JVM GC performance.
Especially for there is a big number of topics served by a single broker.

Modifications

1. Make poolMessage=true when SystemTopicBasedTopicPoliciesService component creating a reader
2. Call message.release() manually after process messages.

Verifying this change

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This change is a trivial rework / code cleanup without any test coverage.

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This change is already covered by existing tests, such as (please describe tests).

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This change added tests and can be verified as follows:

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• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

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• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

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Matching PR in forked repository

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.10%. Comparing base (bbc6224) to head (850df7b).
Report is 815 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #23780      +/-   ##
============================================
+ Coverage     73.57%   74.10%   +0.53%     
+ Complexity    32624    31729     -895     
============================================
  Files          1877     1853      -24     
  Lines        139502   143377    +3875     
  Branches      15299    16276     +977     
============================================
+ Hits         102638   106254    +3616     
+ Misses        28908    28735     -173     
- Partials       7956     8388     +432     

Flag	Coverage Δ
inttests	26.70% <100.00%> (+2.11%)	⬆️
systests	23.21% <66.66%> (-1.11%)	⬇️
unittests	73.62% <100.00%> (+0.77%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../service/SystemTopicBasedTopicPoliciesService.java	75.57% <100.00%> (+1.37%)	⬆️
...roker/systopic/TopicPoliciesSystemTopicClient.java	72.83% <100.00%> (+0.68%)	⬆️

... and 1018 files with indirect coverage changes