While working on the DevTools profiler, I've noticed that durations are sometimes incorrect. This seems to be vaguely related to high/low priority state updates. Need to track this down more so I'm filing an issue for myself.
if (!enableProfilerTimer) {
    return;
  }
  if (__DEV__) {
    warningWithoutStack(
      fiberStack.length === 0,
      'Expected an empty stack. Something was not reset properly.',
    );
  }
}
function markActualRenderTimeStarted(fiber: Fiber): void {
  if (!enableProfilerTimer) {
    return;
  }
  if (__DEV__) {
    fiberStack.push(fiber);
  }
  fiber.actualDuration =
    now() - ((fiber.actualDuration: any): number) - totalElapsedPauseTime;
  fiber.actualStartTime = now();
}
function pauseActualRenderTimerIfRunning(): void {