code: func (s *Server) SendSync(m Message) error {
  	var eg errgroup.Group
  	msg, err := s.serializer.Marshal(m)
  	if err != nil {
  		return fmt.Errorf("marshaling message: %v", err)
  	}
  	msg = append([]byte{getMessageType(m)}, msg...)
  
  	for _, node := range s.cluster.Nodes() {
  		node := node
  		// Don't forward the message to ourselves.
  		if s.uri == node.URI {
  			continue
  		}
  
  		eg.Go(func() error {
  			return s.defaultClient.SendMessage(context.Background(), &node.URI, msg)
  		})
  	}
  
  	return eg.Wait()
  }
docs: // SendSync represents an implementation of Broadcaster.