@Override
  public boolean mayHaveChildren(int id) {
    try {
      return vfsPeer.mayHaveChildren(id);
    }
    catch (IllegalArgumentException e) {
      //here we +/- sure the id _should_ exist => give VFS a kick to rebuild
      vfsPeer.handleError(e);
      throw e;
    }
  }
@Override
  public boolean mayHaveChildren(int id)