[Do not Merge] [Otlp Exporter] Remove Google.Protobuf and Grpc.Net.Client dependency

[vishweshbankwar]

Towards #5730 #5450

Changes

• Removes Google.Protobuf dependency for serialization for Trace exporter. Implements a custom Serializer as per the OTLP spec.
• For Grpc, uses HttpClient for sending HTTP/2 requests. Dependency on Grpc.Core.Api is kept as is for error handling (creating RpcExceptions) (Can be removed as well by forking certain types).
• Custom implementation is put behind a feature flag OTEL_DOTNET_EXPERIMENTAL_USE_CUSTOM_PROTOBUF_SERIALIZER for now.

Note: This is a proof of concept PR to collect the initial feedback and is not intended to be merged. Smaller follow-up PRs will be done once the approach is finalized.

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[bot]]

Codecov Report

Attention: Patch coverage is 76.60377% with 248 lines in your changes missing coverage. Please review.

Project coverage is 85.31%. Comparing base (6250307) to head (5e78598). Report is 298 commits behind head on main.

Files	Patch %	Lines
...entation/Custom/ExportClient/GrpcProtocolHelper.cs	57.01%	49 Missing :warning:
...rotocol/Implementation/Custom/Serializer/Writer.cs	54.71%	48 Missing :warning:
.../Implementation/Custom/Serializer/OtlpTagWriter.cs	0.00%	41 Missing :warning:
...TelemetryProtocol/OtlpExporterOptionsExtensions.cs	25.00%	36 Missing :warning:
...ation/Custom/Serializer/WireTypesSizeCalculator.cs	29.03%	22 Missing :warning:
...ol/Implementation/Custom/Transmission/OtlpRetry.cs	77.27%	15 Missing :warning:
...ementation/Custom/Serializer/ActivitySerializer.cs	94.53%	10 Missing :warning:
...tlpExporterPersistentStorageTransmissionHandler.cs	86.15%	9 Missing :warning:
...tation/Custom/ExportClient/OtlpGrpcExportClient.cs	86.53%	7 Missing :warning:
...om/Transmission/OtlpExporterTransmissionHandler.cs	88.23%	4 Missing :warning:
... and 4 more

Additional details and impacted files

[](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) ```diff @@ Coverage Diff @@ ## main #5731 +/- ## ========================================== + Coverage 83.38% 85.31% +1.93% ========================================== Files 297 273 -24 Lines 12531 12103 -428 ========================================== - Hits 10449 10326 -123 + Misses 2082 1777 -305 ``` | [Flag](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `?` | | | [unittests-Project-Experimental](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `85.31% <76.60%> (?)` | | | [unittests-Project-Stable](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | `85.42% <76.60%> (?)` | | Flags with carried forward coverage won't be shown. 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[...tation/Custom/Serializer/ActivitySizeCalculator.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FSerializer%2FActivitySizeCalculator.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9TZXJpYWxpemVyL0FjdGl2aXR5U2l6ZUNhbGN1bGF0b3IuY3M=) | `100.00% <100.00%> (ø)` | | | [...ntation/Custom/Serializer/CommonTypesSerializer.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FSerializer%2FCommonTypesSerializer.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9TZXJpYWxpemVyL0NvbW1vblR5cGVzU2VyaWFsaXplci5jcw==) | `100.00% <100.00%> (ø)` | | | [.../Implementation/Custom/Transmission/RetryHelper.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FTransmission%2FRetryHelper.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9UcmFuc21pc3Npb24vUmV0cnlIZWxwZXIuY3M=) | `100.00% <100.00%> (ø)` | | | [...etryProtocol/Implementation/ExperimentalOptions.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FExperimentalOptions.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0V4cGVyaW1lbnRhbE9wdGlvbnMuY3M=) | `90.90% <100.00%> (-9.10%)` | :arrow_down: | | [...metryProtocol/OtlpTraceExporterHelperExtensions.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FOtlpTraceExporterHelperExtensions.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL090bHBUcmFjZUV4cG9ydGVySGVscGVyRXh0ZW5zaW9ucy5jcw==) | `97.33% <100.00%> (+0.66%)` | :arrow_up: | | [...rter.OpenTelemetryProtocol/OtlpTraceExporterNew.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FOtlpTraceExporterNew.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL090bHBUcmFjZUV4cG9ydGVyTmV3LmNz) | `100.00% <100.00%> (ø)` | | | [...tion/Custom/ExportClient/TrailingHeadersHelpers.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FExportClient%2FTrailingHeadersHelpers.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9FeHBvcnRDbGllbnQvVHJhaWxpbmdIZWFkZXJzSGVscGVycy5jcw==) | `50.00% <50.00%> (ø)` | | | [...ion/Custom/Serializer/CommonTypesSizeCalculator.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FSerializer%2FCommonTypesSizeCalculator.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9TZXJpYWxpemVyL0NvbW1vblR5cGVzU2l6ZUNhbGN1bGF0b3IuY3M=) | `98.00% <98.00%> (ø)` | | | [...ansmission/OtlpExporterRetryTransmissionHandler.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FTransmission%2FOtlpExporterRetryTransmissionHandler.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9UcmFuc21pc3Npb24vT3RscEV4cG9ydGVyUmV0cnlUcmFuc21pc3Npb25IYW5kbGVyLmNz) | `80.00% <80.00%> (ø)` | | | [...tation/Custom/ExportClient/OtlpHttpExportClient.cs](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree&filepath=src%2FOpenTelemetry.Exporter.OpenTelemetryProtocol%2FImplementation%2FCustom%2FExportClient%2FOtlpHttpExportClient.cs&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry#diff-c3JjL09wZW5UZWxlbWV0cnkuRXhwb3J0ZXIuT3BlblRlbGVtZXRyeVByb3RvY29sL0ltcGxlbWVudGF0aW9uL0N1c3RvbS9FeHBvcnRDbGllbnQvT3RscEh0dHBFeHBvcnRDbGllbnQuY3M=) | `91.89% <91.89%> (ø)` | | | ... and [10 more](https://app.codecov.io/gh/open-telemetry/opentelemetry-dotnet/pull/5731?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-telemetry) | | ... and [226 files with indirect coverage 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[rajkumar-rangaraj]

Directions look good to me. When you plan to create smaller PRs, consider adding detailed comments at the top of every method to help ease the review and later debugging process, as most of the methods perform calculations.

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Closed as inactive. Feel free to reopen if this PR is still being worked on.