[otlp] Buffer Size Handling with Retry Logic and OTLP Signal Path

[rajkumar-rangaraj]

Follow up #5977
Design discussion issue #

Changes

Please provide a brief description of the changes here.

• Added exception handling to IncreaseBufferSize and moved it to ProtobufSerializer.
• Added retry logic for the batch in case of buffer overrun.
• Added the missing signal path required to send data to the OTLP endpoint for logs and metrics.

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 21.56863% with 40 lines in your changes missing coverage. Please review.

Project coverage is 83.98%. Comparing base (e3665c9) to head (3fc85c9).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...TelemetryProtocol/OtlpExporterOptionsExtensions.cs	0.00%	16 Missing ⚠️
...ol/Implementation/Serializer/ProtobufSerializer.cs	0.00%	12 Missing ⚠️
...entation/Serializer/ProtobufOtlpTraceSerializer.cs	50.00%	7 Missing ⚠️
...ation/ExportClient/ProtobufOtlpHttpExportClient.cs	0.00%	1 Missing ⚠️
...tlpExporterPersistentStorageTransmissionHandler.cs	0.00%	1 Missing ⚠️
...r.OpenTelemetryProtocol/ProtobufOtlpLogExporter.cs	0.00%	1 Missing ⚠️
...penTelemetryProtocol/ProtobufOtlpMetricExporter.cs	0.00%	1 Missing ⚠️
...OpenTelemetryProtocol/ProtobufOtlpTraceExporter.cs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5988      +/-   ##
==========================================
- Coverage   84.14%   83.98%   -0.17%     
==========================================
  Files         275      275              
  Lines       12560    12582      +22     
==========================================
- Hits        10569    10567       -2     
- Misses       1991     2015      +24     

Flag	Coverage Δ
unittests-Project-Experimental	83.98% <21.56%> (-0.13%)	⬇️
unittests-Project-Stable	83.92% <21.56%> (-0.11%)	⬇️

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

Files with missing lines	Coverage Δ
...tation/OpenTelemetryProtocolExporterEventSource.cs	85.00% <100.00%> (+1.66%)	⬆️
...ation/ExportClient/ProtobufOtlpHttpExportClient.cs	0.00% <0.00%> (ø)
...tlpExporterPersistentStorageTransmissionHandler.cs	0.00% <0.00%> (ø)
...r.OpenTelemetryProtocol/ProtobufOtlpLogExporter.cs	0.00% <0.00%> (ø)
...penTelemetryProtocol/ProtobufOtlpMetricExporter.cs	0.00% <0.00%> (ø)
...OpenTelemetryProtocol/ProtobufOtlpTraceExporter.cs	0.00% <0.00%> (ø)
...entation/Serializer/ProtobufOtlpTraceSerializer.cs	87.35% <50.00%> (-2.29%)	⬇️
...ol/Implementation/Serializer/ProtobufSerializer.cs	87.69% <0.00%> (-8.92%)	⬇️
...TelemetryProtocol/OtlpExporterOptionsExtensions.cs	75.69% <0.00%> (-5.86%)	⬇️

... and 4 files with indirect coverage changes

---- 🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[CodeBlanch]

LGTM