See #17798
}
      while (node.return) {
        node = node.return;
        if ((node.effectTag & Placement) !== NoEffect) {
          return MOUNTING;
        }
      }
    } else {
      while (node.return) {
        node = node.return;
      }
    }
    if (node.tag === HostRoot) {
       T
       r
      return MOUNTED;
    }
     I
     t
    return UNMOUNTED;
  }
   This function is copied from React and should be kept in sync:
   https:github.com/facebook/react/blob/master/packages/react-reconciler/src/ReactFiberTreeReflection.js
   It would be nice if we updated React to inject this function directly (vs just indirectly via findDOMNode).
   BEGIN copied code
  function findCurrentFiberUsingSlowPathById(id: number): Fiber | null {
    const fiber = idToFiberMap.get(id);
    if (fiber == null) {
      console.warn(`Could not find Fiber with id "${id}"`);
      return null;