Can anybody provide a practical example of fastify4 + @apollo/server v4 + @fastify/websocket and Redis for gql subscriptions

Question

I am trying to get graphql subscriptions working through a setup using fastify v4 + @apollo/server v4 + @fastify/websocket and Redis. How would one create the publisher and subscriber and listen to the same /graphql route the apollo handler is? is it even possible in this case?

import { ApolloServer } from '@apollo/server';
import { ApolloServerPluginLandingPageLocalDefault } from '@apollo/server/plugin/landingPage/default';
import fastifyApollo, { fastifyApolloDrainPlugin } from '@as-integrations/fastify';

import Cors from '@fastify/cors';
import { env } from '@lib/env';


import fastifyCookie from '@fastify/cookie';

import { Context } from '@typings/context';

import Fastify from 'fastify';

import { apolloCtxRegisterFn } from 'middleware/apollo-ctx';
import { errorHandler } from 'middleware/error-handler';
import { ctxRequestDecorator } from 'middleware/global-ctx';
import fastifyWebsocket from "@fastify/websocket";

const fastify = Fastify();

await fastify.register(fastifyWebsocket);


const apollo = new ApolloServer<Context>({
    schema: schema, // obtained from somewhere
    plugins: [
        fastifyApolloDrainPlugin(fastify),
        ApolloServerPluginLandingPageLocalDefault({
            includeCookies: true,
        }),
    ],
});

fastify.setErrorHandler(errorHandler);

await apollo.start();

await fastify.register(Cors, {
    ...
        ...
        ...
});

await fastify.register(fastifyCookie, {});
await fastify.register(ctxRequestDecorator);

// the ws server should technically listen to the same `/graphql` route
// can't figure out what the next step is here
// do I register the ws separately and bind it to GET requests on `/graphql`?
// can I register it along with the apollo graphql handler?
await fastify.register(fastifyApollo(apollo), apolloCtxRegisterFn);

await fastify.listen({
    port: env.SERVER_PORT,
});


console.log(` Server ready at http://localhost:${env.SERVER_PORT}/graphql`);