[improve][client]: add --streaming option to topics partitioned-stats-internal

[dlg99]

Motivation

Streaming the stats output directly to the standard output without parsing the response in memory.

Modifications

added --streaming flag for topics stats-internal/partitioned-stats-internal commands to stream the stats.

Verifying this change

• Make sure that the change passes the CI checks.

This change added unit tests.

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

added --streaming flag for topics stats-internal/partitioned-stats-internal commands

• 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: dlg99#21

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 52.17391% with 11 lines in your changes missing coverage. Please review.

Project coverage is 74.52%. Comparing base (bbc6224) to head (cd88109).
Report is 667 commits behind head on master.

Files with missing lines	Patch %	Lines
...pache/pulsar/client/admin/internal/TopicsImpl.java	0.00%	9 Missing ⚠️
...in/java/org/apache/pulsar/admin/cli/CmdTopics.java	85.71%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #23380      +/-   ##
============================================
+ Coverage     73.57%   74.52%   +0.94%     
- Complexity    32624    34468    +1844     
============================================
  Files          1877     1934      +57     
  Lines        139502   145158    +5656     
  Branches      15299    15874     +575     
============================================
+ Hits         102638   108176    +5538     
+ Misses        28908    28679     -229     
- Partials       7956     8303     +347     

Flag	Coverage Δ
inttests	27.71% <0.00%> (+3.13%)	⬆️
systests	24.53% <0.00%> (+0.20%)	⬆️
unittests	73.87% <52.17%> (+1.03%)	⬆️

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

Files with missing lines	Coverage Δ
...in/java/org/apache/pulsar/client/admin/Topics.java	78.57% <ø> (+1.07%)	⬆️
...in/java/org/apache/pulsar/admin/cli/CmdTopics.java	80.01% <85.71%> (-1.16%)	⬇️
...pache/pulsar/client/admin/internal/TopicsImpl.java	82.97% <0.00%> (+0.96%)	⬆️

... and 600 files with indirect coverage changes

[lhotari]

Instead of an InputStream, a Reader would be more appropriate for the interface.

The reason for this is in this case, the payload is most likely UTF-8 encoded which uses multi-byte characters for most non-ascii characters.
When reading in 2048 chunks, a multi-byte character might get split at the boundary which will corrupt the output.

Using a Reader would address this without any additional logic.
A long time ago I worked on such a fix for Gradle, https://issues.gradle.org/browse/GRADLE-3329. In that case there was custom buffering and fixing the issue wasn't trivial. I ended up using java.nio.charset.CharsetDecoder and java.nio.charset.CoderResult#isUnderflow to detect when a byte is missing.

A Reader will buffer the underlying bytes when there's a multi-byte character case and the remaining byte is not yet readable. That's why it's better to rely on a Reader in the interface.

[lhotari]

slightly related #18263

[lhotari]

@dlg99 please address the review feedback, #23380 (review).