code: @Override
    public void close()
      throws IOException
    {
      if (_isClosed.getAndSet(true)) {
        return;
      }
  
      _ss = null;
  
      if (_stream != null) {
        _stream.close();
      }
  
      // XXX: can't be locked because of shutdown
  
      _nativeFd = -1;
      nativeClose(_socketFd);
    }
docs: Closes the socket.