Add performance and compatibility details to EtwManifestEventFormat and EtwSelfDescribingEventFormat docs

[Copilot]

Adds trade-off information between EtwManifestEventFormat and EtwSelfDescribingEventFormat as identified in dotnet/runtime#121180.

Changes

• EtwManifestEventFormat: Documented lower per-event serialization overhead
• EtwSelfDescribingEventFormat: Documented higher capabilities, better listener compatibility (non-TraceEvent library), and higher per-event serialization overhead
• Removed redundant sentence in EtwManifestEventFormat summary
• Added link to EventSource documentation for more information on both enum values

These additions clarify the performance vs. compatibility trade-off when choosing event formats for EventSource configuration.

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Original prompt

Create PR that adds additional information mentioned in dotnet/runtime#121180 (comment) to the to EtwManifestEventFormat and EtwSelfDescribingEventFormat documentation

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[Copilot]

Pull Request Overview

This PR improves the documentation for the EventSourceSettings enumeration by clarifying the differences between manifest-based and self-describing event formats. The changes remove redundant text and add helpful context about performance characteristics and compatibility trade-offs.

• Removed redundant sentence in EtwManifestEventFormat summary
• Added performance and compatibility comparisons for both event format options
• Added reference links to detailed documentation about event format differences

[jkotas]

@noahfalk PTLA - this adds additional information you have mentioned in dotnet/runtime PR discussion a few days ago

[noahfalk]

I thought the comments got synced from the source code. Is that just a one time thing and then future updates should happen here?

[noahfalk]

Text looks good to me, my only question is if it belonged here or in the C# source comments. Thanks!

[jkotas]

I thought the comments got synced from the source code. Is that just a one time thing and then future updates should happen here?

dotnet-api-docs repo is the source of truth for documentation of assemblies with <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile> property set in project file. The automatic sync is one time thing and only for newly introduced APIs in these assemblies. Older assemblies tend to be on this plan, including corelib https://github.com/dotnet/runtime/blob/e8812e7419db9137f20b990786a53ed71e27e11e/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems#L12 .

Source comments are the source of truth for documentation of assemblies that are missing this property. More recently introduced assemblies are on this plan.

Ideally, we would like to have the documentation in the source files for everything, but we have not been able to fund that work.

[noahfalk]

Thanks @jkotas, thats much clearer now. I tried searching around a bit for that info earlier but failed to find it.

[jkotas]

I tried searching around a bit for that info earlier but failed to find it.

I hope dotnet/runtime#121271 will makes this information more discoverable.

[noahfalk]

I also just proposed #12004 which would have most directly helped me find the info earlier.