[Instrumentation.AWSLambda] Incoming FaaS Span attributes: detect and set attribute for cold start

[rypdal]

Fixes #
Design discussion issue #

Changes

Please provide a brief description of the changes here.

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 75.77%. Comparing base (71655ce) to head (4c9503b).
Report is 399 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2037      +/-   ##
==========================================
+ Coverage   73.91%   75.77%   +1.85%     
==========================================
  Files         267       20     -247     
  Lines        9615      227    -9388     
==========================================
- Hits         7107      172    -6935     
+ Misses       2508       55    -2453     

Flag	Coverage Δ
unittests-Instrumentation.AWS	75.77% <ø> (?)

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see 277 files with indirect coverage changes

[Kielek]

LGTM.
Consider if any tests needs to be added/extended.

[Oberon00]

The if can be removed, it's fine to unconditionally set it to false here. Then we also might not need the local variable if you change it after calculating functionTags

[rypdal]

Yes, we can do it. I removed the local variable and moved setting of the internal one after the calculation of functionTags.

[Oberon00]

Yes, this should be unit-testable, please add or extend one to verify the coldstart attribute going from true on the first call to false on subsequent ones.

[rypdal]

LGTM. Consider if any tests needs to be added/extended.

I added test for the cold start tag check.

[Kielek]

One more thing, please extend changelog.

[rypdal]

One more thing, please extend changelog.

changelog has been updated.