socket.io-redis with cluster module

Question

I usually use the cluster module to scale a normal express server, and I want to do the same with socket.io. I found out I can use the socket.io-redis library, but there was no example on how to use it with the cluster module. I already looked at this question: Scaling Socket.IO to multiple Node.js processes using cluster, but socket.io servers were created differently than my current implementation.

Here is my code:

const express = require("express");
const app = express();
const origin = "http://localhost:3000";
const io = require("socket.io")(3001, {
  cors: {
    origin: [origin]
  }
});

io.on("connection", function (socket) {
  // Code here...
});

app.listen(3000);