code: func (s *Server) ServiceNames() []string {
  	s.mu.Lock()
  	defer s.mu.Unlock()
  
  	names := make([]string, 0, len(s.services))
  	for name := range s.services {
  		names = append(names, name)
  	}
  	sort.Strings(names)
  	return names
  }
docs: // ServiceNames returns a sorted list of full names of all registered services.