code: func (s *StanServer) processUnsubscribeRequest(m *nats.Msg) {
  	req := &pb.UnsubscribeRequest{}
  	err := req.Unmarshal(m.Data)
  	if err != nil {
  		s.log.Errorf("Invalid unsub request from %s", m.Subject)
  		s.sendSubscriptionResponseErr(m.Reply, ErrInvalidUnsubReq)
  		return
  	}
  	s.performmUnsubOrCloseSubscription(m, req, false)
  }
docs: // processUnsubscribeRequest will process a unsubscribe request.