code: func (s *serviceConfigWatch) updateAgentRegistration(ns *structs.NodeService) error {
  	return s.agent.addServiceInternal(ns, s.registration.chkTypes, s.registration.persist, s.registration.token, s.registration.source)
  }
docs: // updateAgentRegistration updates the service (and its sidecar, if applicable) in the
  // local state.