[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).


workInProgress._debugOwner = current._debugOwner;
    }
    workInProgress.alternate = current;
    current.alternate = workInProgress;
  } else {
    workInProgress.pendingProps = pendingProps;
    
    
    workInProgress.effectTag = NoEffect;
    
    workInProgress.nextEffect = null;
    workInProgress.firstEffect = null;
    workInProgress.lastEffect = null;
  }
  workInProgress.expirationTime = expirationTime;
  workInProgress.child = current.child;
  workInProgress.memoizedProps = current.memoizedProps;
  workInProgress.memoizedState = current.memoizedState;
  workInProgress.updateQueue = current.updateQueue;
  
  workInProgress.sibling = current.sibling;
  workInProgress.index = current.index;
  workInProgress.ref = current.ref;
  return workInProgress;
}
export function createHostRootFiber(isAsync): Fiber {
  const mode = isAsync ? AsyncMode | StrictMode : NoContext;
  return createFiber(HostRoot, null, null, mode);
}
export function createFiberFromElement(