displayList.churn

Samples SwiftUI’s hosting view display list directly, by reflection. One reading per periodic window, reporting whether the display list changed at all — including the windows before any SwiftUI host exists on screen.


Delivery	stream, interval
Mechanism	reflection
Requires	iOS 17+, basset 0.1.1+

Real output from basset request get, captured against a running app — trimmed from 18 windows to the moment a host appears and the mechanism starts reporting real values:

CAPTURED                  ELAPSED  INSTRUMENT

launch 12789531692424341857
2026-08-23T15:05:12.639Z  +15.0s   swiftui.displayList.churn(swiftUIDisplayList)
├─ windowNanoseconds       999922750
├─ mechanismStatus         no swiftui host on screen
├─ hostCount               0
└─ displayListChangeCount  0
2026-08-23T15:05:13.640Z  +16.0s   swiftui.displayList.churn(swiftUIDisplayList)
├─ windowNanoseconds       1001122166
├─ mechanismStatus         ok
├─ hostCount               1
├─ ivarPathGeneration      26
├─ displayListItemCount    1
├─ displayListSeed         159
└─ displayListChangeCount  0
2026-08-23T15:05:14.639Z  +17.0s   swiftui.displayList.churn(swiftUIDisplayList)
├─ windowNanoseconds       998379084
├─ mechanismStatus         ok
├─ hostCount               1
├─ ivarPathGeneration      26
├─ displayListItemCount    1
├─ displayListSeed         299
└─ displayListChangeCount  1

Getting Started

SDK

CLI

Instruments

Reference

displayList.churn