[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).


): Fiber | null {
    invariant(
      !isWorking,
      'renderRoot was called recursively. This error is likely caused ' +
        'by a bug in React. Please file an issue.',
    );
    isWorking = true;
    
    
    if (
      expirationTime !== nextRenderExpirationTime ||
      root !== nextRoot ||
      nextUnitOfWork === null
    ) {
      
      resetStack();
      nextRoot = root;
      nextRenderExpirationTime = expirationTime;
      nextUnitOfWork = createWorkInProgress(
        nextRoot.current,
        null,
        nextRenderExpirationTime,
      );
      root.pendingCommitExpirationTime = NoWork;
    }
    let didFatal = false;
    startWorkLoopTimer(nextUnitOfWork);
    do {
      try {
        workLoop(isAsync);