<!--
  Note: if the issue is about documentation or the website, please file it at:
  https://github.com/reactjs/reactjs.org/issues/new
-->

**Do you want to request a *feature* or report a *bug*?**
Not sure if its a bug or a feature request.

**What is the current behavior?**
The component given as a fallback to Suspense is remounted each time a lazy child resolves.

https://codesandbox.io/s/z6v6x3n1np
This example shows how a fallback component, which counts up, is mounted more than once.

**What is the expected behavior?**
The fallback is mounted once and is only unmounted when all lazy children are resolved.
In the example the counter would run up to 9.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
react@16.6.0

return;
    }
    const recyclableInstance: Instance = workInProgress.stateNode;
    const currentHostContext = getHostContext();
    let updatePayload = null;
    if (oldProps !== newProps) {
      updatePayload = prepareUpdate(
        recyclableInstance,
        type,
        oldProps,
        newProps,
        rootContainerInstance,
        currentHostContext,
      );
    }
    if (childrenUnchanged && updatePayload === null) {
      
      
      workInProgress.stateNode = currentInstance;
      return;
    }
    let newInstance = cloneInstance(
      currentInstance,
      updatePayload,
      type,
      oldProps,
      newProps,
      workInProgress,
      childrenUnchanged,
      recyclableInstance,