[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).


element: ReactElement,
  mode: TypeOfMode,
  expirationTime: ExpirationTime,
): Fiber {
  let owner = null;
  if (__DEV__) {
    owner = element._owner;
  }
  let fiber;
  const type = element.type;
  const key = element.key;
  let pendingProps = element.props;
  let fiberTag;
  if (typeof type === 'function') {
    fiberTag = shouldConstruct(type) ? ClassComponent : IndeterminateComponent;
  } else if (typeof type === 'string') {
    fiberTag = HostComponent;
  } else {
    switch (type) {
      case REACT_FRAGMENT_TYPE:
        return createFiberFromFragment(
          pendingProps.children,
          mode,
          expirationTime,
          key,
        );
      case REACT_ASYNC_MODE_TYPE:
        fiberTag = Mode;