[Exporter.Geneva] Allow custom string size limit to increase ETW buffer space efficiency

[xiang17]

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

Attention: Patch coverage is 86.20690% with 4 lines in your changes missing coverage. Please review.

Project coverage is 52.89%. Comparing base (71655ce) to head (2b0db5c).
Report is 872 commits behind head on main.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...xporter.Geneva/Internal/ConnectionStringBuilder.cs	72.72%	3 Missing ⚠️
...rter.Geneva/Internal/MsgPack/MsgPackLogExporter.cs	90.90%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2813       +/-   ##
===========================================
- Coverage   73.91%   52.89%   -21.02%     
===========================================
  Files         267       55      -212     
  Lines        9615     5091     -4524     
===========================================
- Hits         7107     2693     -4414     
+ Misses       2508     2398      -110     

Flag	Coverage Δ
unittests-Exporter.Geneva	52.89% <86.20%> (?)

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

Files with missing lines	Coverage Δ
...r.Geneva/Internal/MsgPack/MessagePackSerializer.cs	91.80% <100.00%> (ø)
...rter.Geneva/Internal/MsgPack/MsgPackLogExporter.cs	92.20% <90.90%> (ø)
...xporter.Geneva/Internal/ConnectionStringBuilder.cs	92.85% <72.72%> (-0.09%)	⬇️

... and 250 files with indirect coverage changes

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[rajkumar-rangaraj]

LGTM

[Copilot]

Pull Request Overview

This PR introduces a new connection‐string parameter to let users override the maximum MessagePack string length, propagates that limit through the exporter and serializer, adds tests for the new behavior, and updates documentation.

• Adds PrivatePreviewLogMessagePackStringSizeLimit setting to ConnectionStringBuilder with default and validation
• Exposes the new limit to MsgPackLogExporter and enforces it against the buffer size
• Updates MessagePackSerializer to honor a configurable size limit and adds related unit tests

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/OpenTelemetry.Exporter.Geneva/Internal/ConnectionStringBuilder.cs	Introduced PrivatePreviewLogMessagePackStringSizeLimit property with parsing and validation
src/OpenTelemetry.Exporter.Geneva/Internal/MsgPack/MsgPackLogExporter.cs	Wired new size limit into the exporter and added a range check
src/OpenTelemetry.Exporter.Geneva/Internal/MsgPack/MessagePackSerializer.cs	Extended serialization APIs to accept a custom char‐count limit
test/OpenTelemetry.Exporter.Geneva.Tests/MsgPackLogExporterTests.cs	Added tests for default, valid, negative, and too‐large limits
test/OpenTelemetry.Exporter.Geneva.Tests/MessagePackSerializerTests.cs	Updated ASCII and Unicode serialization tests to exercise truncation
test/OpenTelemetry.Exporter.Geneva.Tests/ConnectionStringBuilderTests.cs	Added tests to verify parsing and validation of the new parameter
src/OpenTelemetry.Exporter.Geneva/CHANGELOG.md	Documented the new experimental connection‐string option

Comments suppressed due to low confidence (2)

src/OpenTelemetry.Exporter.Geneva/Internal/ConnectionStringBuilder.cs:85

• Add XML documentation above this property to describe the PrivatePreviewLogMessagePackStringSizeLimit parameter, its default value, valid range, and behavior when omitted or out of range.

public int PrivatePreviewLogMessagePackStringSizeLimit

test/OpenTelemetry.Exporter.Geneva.Tests/MessagePackSerializerTests.cs:297

• Consider adding tests that pass a non-default sizeLimit argument to MessagePackSerializer_TestASCIIStringSerialization and TestUnicodeStringSerialization to verify custom limits behave as expected.

this.MessagePackSerializer_TestASCIIStringSerialization(new string('Z', 1 << 15));