如何配置graphql-flutter和apollo服务器使应用程序停止从websocket断开连接

flutter pub add graphql_flutter
npm install apollo-server

import 'package:graphql_flutter/graphql_flutter.dart';

void main() {
  final HttpLink link = HttpLink('YOUR_GRAPHQL_API_ENDPOINT');

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

  runApp(MyApp(client: client));
}

class MyApp extends StatelessWidget {
  final ValueNotifier<GraphQLClient> client;

  const MyApp({Key key, this.client}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return GraphQLProvider(
      client: client,
      child: MaterialApp(
        title: 'Your App',
        home: HomeScreen(),
      ),
    );
  }
}

const { ApolloServer, gql } = require('apollo-server');

const typeDefs = gql`
  type Query {
    hello: String
  }
`;

const resolvers = {
  Query: {
    hello: () => 'Hello, world!',
  },
};

const server = new ApolloServer({ typeDefs, resolvers });

server.listen().then(({ url }) => {
  console.log(`Server ready at ${url}`);
});

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

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
      ),
      body: Query(
        options: QueryOptions(
          document: gql('YOUR_GRAPHQL_QUERY'),
        ),
        builder: (QueryResult result, {VoidCallback refetch}) {
          if (result.hasException) {
            return Text(result.exception.toString());
          }

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

          // 处理返回的数据
          final data = result.data['YOUR_DATA_FIELD'];

          return Text(data.toString());
        },
      ),
    );
  }
}