code: function() {
    var udpServer = dgram.createSocket('udp4');
    // binding required for getting responses
    udpServer.bind();
    udpServer.on('error', function () {});
    getUdpServer = function() {
      return udpServer;
    };
    return getUdpServer();
  }
docs: UdpServer Singleton, using self-redefining function