code: func (s *Stack) SetNetworkProtocolOption(network tcpip.NetworkProtocolNumber, option interface{}) *tcpip.Error {
  	netProto, ok := s.networkProtocols[network]
  	if !ok {
  		return tcpip.ErrUnknownProtocol
  	}
  	return netProto.SetOption(option)
  }
docs: // SetNetworkProtocolOption allows configuring individual protocol level
  // options. This method returns an error if the protocol is not supported or
  // option is not supported by the protocol implementation or the provided value
  // is incorrect.