Performance

Performance instrumentation covers startup and rendering responsiveness.

Startup

Startup tracking creates spans for the app launch path and can mark first-frame or first-interaction milestones.

Frame timings

The package can emit metrics for:

• total frame duration
• build duration
• raster duration
• slow frame count
• jank frame count

Control thresholds with:

• slowFrameThreshold
• jankFrameThreshold

UI stalls

The UI stall observer uses a heuristic event-loop check to detect long stalls.

Control this with:

• trackUiStalls
• uiStallThreshold
• uiStallCheckInterval

Practical note

Frame timing and UI stall instrumentation are useful, but they are not free. Keep them enabled deliberately in environments where the signal is worth the extra runtime work.