flutter bloc软件包yeild在状态管理中不起作用

Question

  

虽然setData方法中的这种收益不起作用，但是有人可以描述吗？如果没有从setData发送任何参数，那么它将起作用。或者任何人都可以解释它在bloc中的工作原理。

class LoginerrorBloc extends Bloc<LoginerrorEvent, LoginerrorState> {
  @override
  LoginerrorState get initialState => InitialLoginerrorState();

  @override
  Stream<LoginerrorState> mapEventToState(
    LoginerrorEvent event,
  ) async* {
    if (event is LoginEvent) {
       yield LoginLoading();
      try {

        final url = apiUrl + 'login';
        http.Response response = await http.post(url,
            body: {'contact': event.contact, 'password': event.password});

        if (response.statusCode == 200) {
          // var res = Authenticate.fromJson(true);
           yield* setData(Login.fromJson(jsonDecode(response.body)));

        } else if (response.statusCode == 401) {
          var res = LoginError.fromJson(jsonDecode(response.body));
          yield LoginErrorState(res);
        } else {
          var res = LoginError.fromJson({'message': 'Internal Server Error'});
          yield LoginErrorState(res);
        }
      } catch (e) {
        var res = NetworkError.fromJson({'message': 'Internal Server Error'});
        yield NetworkErrorState(res);
      }
    }
  }

  Stream<LoginerrorState> setData(data) async* {
          yield AuthenticateState();

  }
}