[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 batches = completedBatches;
      completedBatches = null;
      for (let i = 0; i < batches.length; i++) {
        const batch = batches[i];
        try {
          batch._onComplete();
        } catch (error) {
          if (!hasUnhandledError) {
            hasUnhandledError = true;
            unhandledError = error;
          }
        }
      }
    }
    if (hasUnhandledError) {
      const error = unhandledError;
      unhandledError = null;
      hasUnhandledError = false;
      throw error;
    }
  }
  function performWorkOnRoot(
    root: FiberRoot,
    expirationTime: ExpirationTime,
    isAsync: boolean,
  ) {
    invariant(
      !isRendering,
      'performWorkOnRoot was called recursively. This error is likely caused ' +
        'by a bug in React. Please file an issue.',