Feedback for converting eventsource metadata list to a dict

[rcj1]

Adding the formatting and other minor changes from code review

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[Copilot]

Pull Request Overview

This PR merges the formatting and minor refactoring updates from GH99816 into main.

• Switched m_eventData from an array to a Dictionary<int, EventMetadata>
• Refactored all direct index accesses to use CollectionsMarshal.GetValueRefOrNullRef
• Updated loops over m_eventData to iterate dictionary keys or values, and added necessary using directives

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/NativeRuntimeEventSource.cs	Replaced array checks and payload decoding with dictionary lookups
src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventSource.cs	Converted m_eventData storage to Dictionary<int, EventMetadata> and updated indexing, iteration, and event dispatch logic

Comments suppressed due to low confidence (2)

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/NativeRuntimeEventSource.cs:54

• Switching from an array to a dictionary lookup in this hot path may introduce noticeable overhead. Consider caching the metadata reference or benchmarking this change to ensure performance remains acceptable.

            ref EventMetadata metadata = ref CollectionsMarshal.GetValueRefOrNullRef(m_eventData!, (int)eventID);

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventSource.cs:787

• [nitpick] Iterating dictionary keys may produce a different order than the original array sequence. If event order matters, consider sorting the keys or otherwise preserving the prior order semantics.

            foreach (int metaKey in m_eventData.Keys)

[noahfalk]

LGTM, thanks!