Improve trace timestamp accuracy under concurrent event recording

[rahul-lohra]

Goal

Close #AND-1265

Improve the accuracy of trace timestamps by recording the timestamp when the trace event is created rather than when it is inserted into the tracer buffer.

Previously, timestamps were generated inside the synchronized buffer section. Under contention, a thread could wait to acquire the lock before recording its timestamp, causing the recorded time to reflect lock acquisition order rather than the actual time the event occurred.

By capturing the timestamp before acquiring the buffer lock, trace records more accurately represent when the underlying event was observed by the SDK.

Implementation

• Moved TraceRecord creation outside the synchronized buffer section.
• Capture System.currentTimeMillis() before attempting to acquire the tracer lock.
• Preserve the existing synchronization strategy for buffer mutations.
• No changes to trace serialization, buffering, rollback behavior, or upload logic.

Before:

• Timestamp represented when the tracer accepted the event into the buffer.

After:

• Timestamp represents when the event was observed and trace() was invoked.

This change improves the temporal accuracy of analytics and debugging traces when multiple threads are recording events concurrently.

🎨 UI Changes

None

Testing

Visit Stream Demo App's Dashboard to see the tracer events

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled, or the PR is bot-authored.
• An issue is linked (Linear ticket or GitHub issue), or the PR is bot-authored.

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-video-android-core	12.27 MB	12.27 MB	0.00 MB	🟢
stream-video-android-ui-xml	5.68 MB	5.68 MB	0.00 MB	🟢
stream-video-android-ui-compose	6.20 MB	6.20 MB	0.00 MB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: 4ff38456-1011-4ed6-82c0-2d9383bbdd4d

📥 Commits

Reviewing files that changed from the base of the PR and between 6035a0d and 5e35534.

📒 Files selected for processing (2)

• stream-video-android-core/src/main/kotlin/io/getstream/video/android/core/trace/TraceRecord.kt
• stream-video-android-core/src/test/kotlin/io/getstream/video/android/core/trace/TraceRecordTest.kt

👮 Files not reviewed due to content moderation or server errors (2)

• stream-video-android-core/src/main/kotlin/io/getstream/video/android/core/trace/TraceRecord.kt
• stream-video-android-core/src/test/kotlin/io/getstream/video/android/core/trace/TraceRecordTest.kt

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Warning

Walkthrough skipped

File diffs could not be summarized.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch bugfix/rahullohra/tracer-timestamp-fifo

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