[This example](https://codesandbox.io/s/1zn2o513pq) presents a huge performance drop between React 16.2 and React 16.3.

In investigated it and noticed several things:

- Perfomance drop is only visible using development bundle
- This is not related to styled-components (a simple div presents the same problem)
- I tried to investigate in performance tab of Chrome dev tools and I noticed that I get React measures even without "?react_perf"
- React Tree Reconciliation seems very long, do not know why

It is not a big problem for me, but it looks weird, so I decided to [share it on Twitter](https://twitter.com/neoziro/status/979756579296817154),  then @gaearon [invited me to submit an issue about it](https://twitter.com/dan_abramov/status/980036013518139398).


const current = workInProgress.alternate;
      if (__DEV__) {
        ReactDebugCurrentFiber.setCurrentFiber(workInProgress);
      }
      const returnFiber = workInProgress.return;
      const siblingFiber = workInProgress.sibling;
      if ((workInProgress.effectTag & Incomplete) === NoEffect) {
        
        let next = completeWork(
          current,
          workInProgress,
          nextRenderExpirationTime,
        );
        stopWorkTimer(workInProgress);
        resetExpirationTime(workInProgress, nextRenderExpirationTime);
        if (__DEV__) {
          ReactDebugCurrentFiber.resetCurrentFiber();
        }
        if (next !== null) {
          stopWorkTimer(workInProgress);
          if (__DEV__ && ReactFiberInstrumentation.debugTool) {
            ReactFiberInstrumentation.debugTool.onCompleteWork(workInProgress);
          }