[repo/examples] Prepare to .NET9

[Kielek]

.NET 9 brings new set of analyzers.
Analyzers are enabled

opentelemetry-dotnet-contrib/build/Common.props

Line 13 in cf14a5a

<AnalysisLevel>latest-all</AnalysisLevel>

and will be included in pipeline when .NET SDK is updated.

Changes

Fix new warnings by building projects locally with .NET9 SDK RC2

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• [ ] Unit tests added/updated
• [ ] Appropriate CHANGELOG.md files updated for non-trivial changes
• [ ] Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.36%. Comparing base (71655ce) to head (0613530).
Report is 582 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2251       +/-   ##
===========================================
- Coverage   73.91%   61.36%   -12.56%     
===========================================
  Files         267       73      -194     
  Lines        9615     2073     -7542     
===========================================
- Hits         7107     1272     -5835     
+ Misses       2508      801     -1707     

Flag	Coverage Δ
unittests-Instrumentation.AspNet	77.00% <ø> (?)
unittests-Instrumentation.ConfluentKafka	14.12% <ø> (?)
unittests-Instrumentation.Owin	85.97% <ø> (?)
unittests-Instrumentation.Process	100.00% <ø> (?)
unittests-Instrumentation.Runtime	97.53% <ø> (?)
unittests-Instrumentation.Wcf	78.47% <ø> (?)

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

see 292 files with indirect coverage changes

[CodeBlanch]

I just tested this. AspNetCore won't auto-register internal controller so this effectively breaks the app. Curious, what is the warning you are getting spurring this change?

[Kielek]

dotnet format opentelemetry-dotnet-contrib.sln when executing in .NET9 SDK context (I just remove global.json file on my env).

It was one of the reasons to mark is as in progress - the second one, some differences in formatting between .NET8 (CI) and .NET9.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.