const mountedRoots = hook.getFiberRoots(rendererID);
    const current = root.current;
    const isKnownRoot = mountedRoots.has(root);
    const isUnmounting =
      current.memoizedState == null || current.memoizedState.element == null;
    
    if (!isKnownRoot && !isUnmounting) {
      mountedRoots.add(root);
    } else if (isKnownRoot && isUnmounting) {
      mountedRoots.delete(root);
    }
    const rendererInterface = rendererInterfaces.get(rendererID);
    if (rendererInterface != null) {
      rendererInterface.handleCommitFiberRoot(root, priorityLevel);
    }
  }
  
  const fiberRoots = {};
  const rendererInterfaces = new Map();
  const listeners = {};
  const renderers = new Map();
  const hook: DevToolsHook = {
    rendererInterfaces,
    listeners,
    
    renderers,