code: function createDgramServer(options = {}) {
    let isExternalSocket = false;
  
    if (options.socket instanceof dgram.Socket) {
      isExternalSocket = true;
    }
  
    const socket = isExternalSocket ? options.socket : dgram.createSocket('udp4');
    const server = new StunServer(socket);
  
    if (!isExternalSocket) {
      socket.on('error', error => server.emit('error', error));
      server.once('close', () => socket.close());
    }
  
    return server;
  }
docs: Creates dgram STUN server.
  @param {Object} [options]
  @param {dgram.Socket} [options.socket] - Optional udp socket.
  @returns {StunServer}