Multi-instance <TimeToInitialDisplay> / <TimeToFullDisplay> coordination; a multi-signal TTID/TTFD system

[alwx]

📢 Type of change

• Bugfix
• New feature
• Enhancement
• Refactoring

📜 Description

Somthing that was requested by our customers: when a screen has multiple async data sources, you can now mount one <TimeToFullDisplay> per source — the TTID/TTFD will get recorded only when all the sources report ready. That makes it possible to use TTID/TTFD when the screen comes with a bunch of individual components to handle not so simple real-world scenarios.

For example, a screen might have:

1. A header component that fetches user profile data
2. A main content area pulling from one API
3. A sidebar or secondary section hitting a completely different service
4. Nested child components several levels deep that each manage their own data fetching

All of these load independently, at different times, and the screen isn't actually fully displayed until every one of them has resolved and rendered. With the current SDK, the only way to handle this is to hoist state management above all of these components, track which ones have finished loading, and only fire the TTFD signal once everything reports in. That's a significant amount of orchestration code that really belongs in the SDK itself.

What we're doing here is basically making it work with multiple TTID/TTFD components to handle multiple signals coming from different sources.

The docs will be updated soon.

💚 How did you test it?

Tests were added.

📝 Checklist

• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled
• I updated the docs if needed.
• I updated the wizard if needed.
• All tests passing
• No breaking changes

🔮 Next steps

[github-actions]

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

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• Multi-instance <TimeToInitialDisplay> / <TimeToFullDisplay> coordination; a multi-signal TTID/TTFD system by alwx in #6090

• Fix PNPM iOS Upload Debug Symbol fail in EAS Build by alwx in #6086
• chore(deps): update Sentry Android Gradle Plugin to v6.6.0 by github-actions in #6085
• fix(e2e): Remove flaky iOS replay assertion from captureReplay test by antonis in #6072
• chore(deps): bump github/codeql-action from 4.35.2 to 4.35.3 by dependabot in #6078
• fix: Prevent shell injection vulnerability in GitHub Actions workflow by fix-it-felix-sentry in #6077
• chore(deps): update Maestro to v2.5.1 by github-actions in #6075

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[alwx]

Moved it back to draft because multi-instance coordination needs to be handled more carefully.