code: func (sn *SimNode) Services() []node.Service {
  	sn.lock.RLock()
  	defer sn.lock.RUnlock()
  	services := make([]node.Service, 0, len(sn.running))
  	for _, service := range sn.running {
  		services = append(services, service)
  	}
  	return services
  }
docs: // Services returns a copy of the underlying services