test: add benchmark tests for baggage

[gruebel]

Relates to #2717 point 2

Changes

• I was not sure about the MAX_KEY_VALUE_PAIRS const, it is currently private so I just duplicated it for the benchmark test. let me know, if you want to make it public or not.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.4%. Comparing base (13fafcb) to head (d6deed3).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2737   +/-   ##
=====================================
  Coverage   79.4%   79.4%           
=====================================
  Files        123     123           
  Lines      22770   22770           
=====================================
  Hits       18092   18092           
  Misses      4678    4678           

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[gruebel]

@cijothomas could you add the performance label to validate the benchmark works in CI as expected.

[cijothomas]

LGTM.
Let us also add some measuring the cost of adding Baggage to Context. It might be required to make Baggage a top-level entry in Context instead of storing it inside Context's hash map to gain perf.

[cijothomas]

@cijothomas could you add the performance label to validate the benchmark works in CI as expected.

oops sorry missed this. We can run targeted benches locally for now. The CI runs entire set, which is quite expensive, and not sure if that is something CNCF encourages us to do...