fix: data race in adka2a integration

[yarolegovich]

Event processor is delaying some events until the whole LLM response is consumed to send them as terminal events.
Those events were referencing the same metadata as events sent before the delayed dispatch.
Metadata was accessed by task update processor leading to a race with meta modification during terminal event dispatch.

The fix is to make delayed events reference metadata shallow copy so that the original metadata is not affected by root-level key updates.

Fixes nightly.

[gemini-code-assist]

Summary of Changes

Hello @yarolegovich, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a critical data race in the adka2a integration. Previously, delayed terminal events would reference the same metadata as earlier events, leading to race conditions when the metadata was modified concurrently. The fix ensures that delayed events operate on a shallow copy of the metadata, thereby preventing these race conditions and enhancing the stability and correctness of event processing.

Highlights

• Data Race Resolution: Resolved a data race condition within the adka2a integration's event processing logic, specifically concerning delayed terminal events.
• Metadata Shallow Copying: Implemented shallow copying of event metadata for delayed terminal events to prevent concurrent modification issues.
• Usage of maps.Clone: Utilized the maps.Clone function to ensure that metadata passed to delayed events is a distinct copy, safeguarding the original metadata from unintended changes.

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[gemini-code-assist]

Code Review

This pull request effectively resolves a data race within the adka2a integration by ensuring metadata for delayed events is properly isolated. The core of the fix is the strategic use of maps.Clone to create shallow copies of metadata maps. This prevents shared state modification when events are queued for later dispatch, specifically for terminal failure and completion events. The changes are correct, well-targeted, and improve the code's robustness against concurrent data access issues. Additionally, replacing make and maps.Copy with maps.Clone is a welcome simplification.

[kdroste-google]

Please add comments explaining reason why we have to copy at those points

[kdroste-google]

LGTM