Flutter IsolateClient Paging

links.dart

import 'package:built_collection/src/list.dart';
import 'package:ferry/ferry.dart';
import 'package:ferry_test/graphql/queries/__generated__/reviews.data.gql.dart';
import 'package:flutter/material.dart';
import 'package:gql_exec/gql_exec.dart';
import 'package:gql_link/gql_link.dart';

class ReviewsAutoResponderTerminalLink extends Link {
  @override
  Stream<Response> request(
    Request request, [
    forward,
  ]) =>
      Stream.value(Response(
          response: const {},
          data: GReviewsData((b) {
            var offset = request.variables['offset'] as int;
            var first = request.variables['first'] as int;

            for (int i = offset; i < (offset + first); i++) {
              var review = GReviewsData_reviews(
                (b) => b
                  ..id = '$i'
                  ..stars = 5,
              );
              b.reviews.add(review);
            }
            return b;
          }).toJson()));
}

main.dart

import 'dart:isolate';
import 'package:uuid/uuid.dart';
import 'package:ferry/ferry.dart';
import 'package:ferry_flutter/ferry_flutter.dart';
import 'package:ferry/ferry_isolate.dart';
import 'package:ferry_test/graphql/queries/__generated__/reviews.data.gql.dart';
import 'package:ferry_test/graphql/queries/__generated__/reviews.req.gql.dart';
import 'package:ferry_test/graphql/queries/__generated__/reviews.var.gql.dart';
import 'package:ferry_test/links.dart';
import 'package:flutter/material.dart';

GReviewsData? _mergeReviews(GReviewsData? previous, GReviewsData? result) {
  final merged =
      previous?.rebuild((b) => b..reviews.addAll(result?.reviews ?? [])) ??
          result;
  return merged;
}

Future<Client> _initClient(Null params, SendPort? sendPort) async {
  return Client(link: ReviewsAutoResponderTerminalLink());
}

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _offset = 0;
  late GReviewsReq _request;
  IsolateClient? _client = null;
  late Uuid uuid;

  _MyHomePageState() {
    uuid = const Uuid();
    _request = GReviewsReq((b) => b
      ..requestId = uuid.v4()
      ..vars.first = 0
      ..vars.offset = _offset);
  }

  Future<bool> _init() async {
    _client = await IsolateClient.create(_initClient, params: null);
    return true;
  }

  Future _reset() async {
    _offset = 0;

    _request = _request.rebuild((b) => b
      ..fetchPolicy = FetchPolicy.CacheAndNetwork
      //..requestId = uuid.v4()
      ..vars.first = 0
      ..vars.offset = _offset);

    await _client!.addRequestToRequestController(_request);
  }

  Future _page() async {
    _offset++;

    final req = _request.rebuild((b) => b
      ..fetchPolicy = FetchPolicy.CacheAndNetwork
      ..updateResult = _mergeReviews
      ..vars.first = 1
      ..vars.offset = _offset);

    await _client!.addRequestToRequestController(req);
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
        future: _init(),
        builder: (context, snapshot) {
          if (!snapshot.hasData) return const CircularProgressIndicator();
          return Scaffold(
            appBar: AppBar(
              title: Text(widget.title),
            ),
            body: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  const Text(
                    'You have pushed the button this many times:',
                  ),
                  Operation<GReviewsData, GReviewsVars>(
                    client: _client!,
                    operationRequest: _request,
                    builder: (context, response, error) {
                      if (response?.loading == true) {
                        return const CircularProgressIndicator();
                      }
                      return Text(
                        '${response?.data?.reviews?.length ?? 0}',
                        style: Theme.of(context).textTheme.headline4,
                      );
                    },
                  ),
                  TextButton(
                    style: ButtonStyle(
                      foregroundColor:
                          MaterialStateProperty.all<Color>(Colors.blue),
                    ),
                    onPressed: () async => await _reset(),
                    child: const Text('Reset'),
                  )
                ],
              ),
            ),
            floatingActionButton: FloatingActionButton(
              onPressed: () async => await _page(),
              tooltip: 'Increment',
              child: const Icon(Icons.add),
            ),
          );
        });
  }
}

pubspec.yaml

name: ferry_test
description: A new Flutter project.

publish_to: 'none'

version: 1.0.0+1

environment:
  sdk: ">=2.17.6 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  ferry: 0.11.2-dev.5
  ferry_flutter: 0.6.2-dev.4
  gql_code_builder: ^0.6.0
  uuid:
  cupertino_icons: ^1.0.2

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_lints: ^2.0.0

flutter:
  uses-material-design: true

On line. 76 of main.dart, if I uncomment this line, then my refresh doesnt work. I feel I may be misunderstanding the role of the request ID.