[exporter/debug] feat: add dropped* attributes to output

[khpeet]

Description

Added logging output for:

• DroppedAttributesCount
• DroppedEventsCount
• DroppedLinksCount

Link to tracking issue

Fixes #14202

Testing

Added validation output to two_spans.out and traces_with_entity_refs.out

Documentation

Added changelog yaml entry summarizing the issue and fix.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.15%. Comparing base (a0cbea7) to head (fb58f11).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14217      +/-   ##
==========================================
- Coverage   92.17%   92.15%   -0.02%     
==========================================
  Files         668      668              
  Lines       41467    41470       +3     
==========================================
- Hits        38221    38216       -5     
- Misses       2213     2218       +5     
- Partials     1033     1036       +3     

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[andrzej-stencel]

Thanks @khpeet for this contribution 🙏 I have one suggestion for the ordering, please let me know what you think.

[khpeet]

Thanks for the review @andrzej-stencel - fixed!

[andrzej-stencel]

Thanks!

[andrzej-stencel]

This is a bit verbose, I'd rather have buf.logAttr("DroppedAttributesCount", span.DroppedAttributesCount()), but this currently results in funny output like DroppedAttributesCount: %!s(uint32=0). Would be nice to fix the logAttr method in a separate change.

[codspeed-hq]

CodSpeed Performance Report

Merging #14217 will degrade performances by 51.67%

_{Comparing khpeet:main (fb58f11) with main (a0cbea7)}

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Summary

❌ 4 regressions
✅ 69 untouched

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	BenchmarkTraceSizeSpanCount	29 ns	60 ns	-51.67%
❌	with_an_existing_value	29 ns	60 ns	-51.67%
❌	with_a_duplicate_value	29 ns	60 ns	-51.67%
❌	with_a_new_value	29 ns	60 ns	-51.67%