如何在GraphQL flutter中替换"OptimisticCache“？

import 'package:flutter/material.dart';
import 'package:graphql_flutter/graphql_flutter.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final HttpLink httpLink = HttpLink(
      uri: 'https://your-graphql-api.com/graphql',
    );

    final ValueNotifier<GraphQLClient> client = ValueNotifier(
      GraphQLClient(
        link: httpLink,
        cache: GraphQLCache(),
      ),
    );

    return GraphQLProvider(
      client: client,
      child: CacheProvider(
        child: MaterialApp(
          title: 'GraphQL Flutter Demo',
          theme: ThemeData(
            primarySwatch: Colors.blue,
          ),
          home: MyHomePage(),
        ),
      ),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final GraphQLClient client = GraphQLProvider.of(context).client;

    return Scaffold(
      appBar: AppBar(
        title: Text('GraphQL Flutter Demo'),
      ),
      body: Query(
        options: QueryOptions(
          document: gql('your-query-here'),
        ),
        builder: (QueryResult result, {VoidCallback refetch}) {
          if (result.hasException) {
            return Text(result.exception.toString());
          }

          if (result.isLoading) {
            return CircularProgressIndicator();
          }

          final data = result.data;

          // Update cache with optimistic response
          final optimisticResponse = {
            // Your optimistic response data here
          };

          final updateCacheHandler = (dynamic cache, QueryResult response) {
            // Update cache with response data
          };

          return Mutation(
            options: MutationOptions(
              document: gql('your-mutation-here'),
              optimisticResponse: optimisticResponse,
              updateCacheHandler: updateCacheHandler,
            ),
            builder: (RunMutation runMutation, QueryResult mutationResult) {
              return RaisedButton(
                onPressed: () {
                  runMutation();
                },
                child: Text('Submit'),
              );
            },
          );
        },
      ),
    );
  }
}