Function markRenderDerivedCause

packages/react-reconciler/src/ReactFiberWorkLoop.js:2425–2438

(fiber: Fiber)

}

export function markRenderDerivedCause(fiber: Fiber): void {
  if (enableProfilerTimer && enableComponentPerformanceTrack) {
    if (__DEV__) {
      if (workInProgressUpdateTask === null) {
        // If we don't have a cause associated with this render, it's likely because some
        // other render left work behind on this Fiber. The real cause is this Fiber itself.
        // We use its debugTask as the cause for this render. This might not be the only
        // one when multiple siblings are rendered but they ideally shouldn't be.
        workInProgressUpdateTask =
          fiber._debugTask == null ? null : fiber._debugTask;
      }
    }
  }
}

export function markTransitionStarted() {
  globalMostRecentTransitionTime = now();