api.dart

class Api{
  static Future<dynamic> post(String path,
      {dynamic body, Map<String, dynamic>? params}) async {
    try {
      final resp = await dio.post<Map<String, dynamic>>(path,
          data: body, queryParameters: params);

      return resp.data;
    } catch (e) {
      ApiResources.errorHandlerFunc(e);
    } finally {
      dio.close();
    }
  }
}

update_profile.dart

class ProfileBloc extends Bloc<ProfileEvent, ProfileState> {
  static ProfileState get initialState => ProfileInitialState();

  ProfileBloc() : super(initialState) {
    on<OnUpdateProfile>((event, emit) async {
        emit(UpdateProfileLoading());

        try {
          final FormData entries = FormData.fromMap({
            'image': await MultipartFile.fromFile(event.image),
            'address': MultipartFile.fromString(
              jsonEncode({"street": "Jl. Jalan", "postalCode": "123456"}),
              contentType: MediaType.parse('application/json'),
            ),
          }, ListFormat.multiCompatible);

          final resp =
              await Api.post('/profile/v1/update', body: entries);

          if (resp['code'] == 200) {
            emit(ProfileUpdate());
          } else {
            emit(ProfileUpdateFailure('Cannot send data from server.'));
          }
        }  catch (e) {
          emit(ProfileUpdateFailure('$e'));
        }
      });
  }
}