private void untagSocket(FileDescriptor fd) throws ErrnoException {
   try {
     SocketTagger.get().untag(fd);
   } catch (SocketException e) {
     throw new ErrnoException("socket", EINVAL, e);
   }
 }
 public void untagSocket(Socket socket) throws SocketException {
   SocketTagger.get().untag(socket);
 }