4.x: Enhance Streamable/Streamer and DisposableContainer APIs

[akarnokd]

• Establish an optional channel for per next() efficient cancellation for Streamable.
• Enhance DisposableContainer for supporting better lifecycle management, recursively.
• Enhance various types.
• Add test() operator
• Add create
• Add transform
• Add toFlowable & toStreamable
• Fix many flaky tests

#hms

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.69 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

.github/workflows/entropy-beauty-scan.yml: 4.690

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊

[codecov]

Codecov Report

❌ Patch coverage is 24.13793% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 99.25%. Comparing base (2e84b74) to head (c416dc8).
⚠️ Report is 1 commits behind head on 4.x.

Files with missing lines	Patch %	Lines
...tivex/rxjava4/disposables/CompositeDisposable.java	0.00%	8 Missing ⚠️
.../internal/disposables/ListCompositeDisposable.java	0.00%	8 Missing ⚠️
.../main/java/io/reactivex/rxjava4/core/Streamer.java	50.00%	3 Missing and 1 partial ⚠️
...tivex/rxjava4/disposables/DisposableContainer.java	50.00%	2 Missing ⚠️

❌ Your patch check has failed because the patch coverage (24.13%) is below the target coverage (95.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff              @@
##                4.x    #8092      +/-   ##
============================================
- Coverage     99.29%   99.25%   -0.04%     
- Complexity     6829     6833       +4     
============================================
  Files           764      765       +1     
  Lines         48246    48274      +28     
  Branches       6470     6473       +3     
============================================
+ Hits          47905    47916      +11     
- Misses          210      228      +18     
+ Partials        131      130       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

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• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.69 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

.github/workflows/entropy-beauty-scan.yml: 4.690

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.69 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

.github/workflows/entropy-beauty-scan.yml: 4.690

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.69 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

.github/workflows/entropy-beauty-scan.yml: 4.690

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.69 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

.github/workflows/entropy-beauty-scan.yml: 4.690

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊