[improve][broker] Skip unloading when bundle throughput is zero (ExtensibleLoadManagerImpl only)

[heesung-sn]

Motivation

If throughput is zero, we better skip the unloading. Otherwise, leader could keep unloading zero throughput bundles back and forth.

Modifications

• do not report zero throughput bundles in the bundle load reporter
• do not unload zero throughput bundles in the TransferShedder

Verifying this change

• Make sure that the change passes the CI checks.

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:

[codelipenghui]

/pulsarbot run-failure-checks

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 62.50000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 74.33%. Comparing base (bbc6224) to head (0d7d60a).
Report is 743 commits behind head on master.

Files with missing lines	Patch %	Lines
...dbalance/extensions/scheduler/TransferShedder.java	40.00%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #23626      +/-   ##
============================================
+ Coverage     73.57%   74.33%   +0.76%     
- Complexity    32624    34454    +1830     
============================================
  Files          1877     1944      +67     
  Lines        139502   147144    +7642     
  Branches      15299    16228     +929     
============================================
+ Hits         102638   109383    +6745     
- Misses        28908    29328     +420     
- Partials       7956     8433     +477     

Flag	Coverage Δ
inttests	27.34% <37.50%> (+2.75%)	⬆️
systests	24.34% <0.00%> (+0.02%)	⬆️
unittests	73.72% <62.50%> (+0.87%)	⬆️

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

Files with missing lines	Coverage Δ
...ker/loadbalance/extensions/models/TopKBundles.java	91.13% <100.00%> (+0.34%)	⬆️
...dbalance/extensions/scheduler/TransferShedder.java	81.11% <40.00%> (-1.81%)	⬇️

... and 659 files with indirect coverage changes

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles

[lhotari]

LGTM