code: func (s *UDPSession) SetNoDelay(nodelay, interval, resend, nc int) {
  	s.mu.Lock()
  	defer s.mu.Unlock()
  	s.kcp.NoDelay(nodelay, interval, resend, nc)
  }
docs: // SetNoDelay calls nodelay() of kcp
  // https://github.com/skywind3000/kcp/blob/master/README.en.md#protocol-configuration