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.
stopWorkTimer(workInProgress);
      resetChildExpirationTime(workInProgress, nextRenderExpirationTime);
      if (__DEV__) {
        ReactCurrentFiber.resetCurrentFiber();
      }
      if (next !== null) {
        stopWorkTimer(workInProgress);
        if (__DEV__ && ReactFiberInstrumentation.debugTool) {
          ReactFiberInstrumentation.debugTool.onCompleteWork(workInProgress);
        }
        
        
        return next;
      }
      if (
        returnFiber !== null &&
        
        (returnFiber.effectTag & Incomplete) === NoEffect
      ) {
        
        
        
        if (returnFiber.firstEffect === null) {
          returnFiber.firstEffect = workInProgress.firstEffect;
        }
        if (workInProgress.lastEffect !== null) {
          if (returnFiber.lastEffect !== null) {
            returnFiber.lastEffect.nextEffect = workInProgress.firstEffect;
          }
          returnFiber.lastEffect = workInProgress.lastEffect;