[improve][broker] Reduce memory occupation of InMemoryRedeliveryTracker.

[thetumbled]

Motivation

Reduce memory occupation of the InMemoryRedeliveryTracker.

Modifications

Use Long2ObjectMap<Long2IntMap> to replace ConcurrentLongLongPairHashMap.

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

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

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

If the box was checked, please highlight the changes

• 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

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository: thetumbled#66

[lhotari]

LGTM, good work @thetumbled

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 63.15789% with 14 lines in your changes missing coverage. Please review.

Project coverage is 74.34%. Comparing base (bbc6224) to head (c37e605).
Report is 751 commits behind head on master.

Files with missing lines	Patch %	Lines
...lsar/broker/service/InMemoryRedeliveryTracker.java	63.15%	12 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #23640      +/-   ##
============================================
+ Coverage     73.57%   74.34%   +0.76%     
- Complexity    32624    34997    +2373     
============================================
  Files          1877     1944      +67     
  Lines        139502   147224    +7722     
  Branches      15299    16246     +947     
============================================
+ Hits         102638   109453    +6815     
- Misses        28908    29322     +414     
- Partials       7956     8449     +493     

Flag	Coverage Δ
inttests	27.22% <34.21%> (+2.63%)	⬆️
systests	24.29% <63.15%> (-0.03%)	⬇️
unittests	73.73% <63.15%> (+0.88%)	⬆️

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

Files with missing lines	Coverage Δ
...lsar/broker/service/InMemoryRedeliveryTracker.java	65.11% <63.15%> (-30.13%)	⬇️

... and 660 files with indirect coverage changes