Based on my analysis of the React Native source code, I can provide you with concrete examples of high priority events that can run the render pipeline in the UI thread.
From examining the React Native source code, I found that React Native uses a priority-based scheduling system with the following hierarchy (defined in <ref_file file="/home/ubuntu/repos/react-native/packages/react-native/ReactCommon/react/renderer/runtimescheduler/SchedulerPriorityUtils.h" />):
- ImmediatePriority (value 1, timeout 0ms) - Highest priority
- UserBlockingPriority (value 2, timeout 250ms) - Second highest priority
- NormalPriority (value 3, timeout 5s)