https://github.com/cloudflare/workerd/tree/b5de5ab88ab7f034527f1696948a8968fb3ed2f3/samples/tcp

workers.js

import { connect } from 'cloudflare:sockets';

export default {
  async fetch(req, env) {
    const socket = connect({
      hostname: 'neverssl.com',
      port: 80
    });

    const writer = socket.writable.getWriter()
    const encoder = new TextEncoder();
    const encoded = encoder.encode("GET / HTTP/1.1\r\nHost: neverssl.com\r\n\r\n");
    await writer.write(encoded);

    const reader = socket.readable.getReader();
    const decoder = new TextDecoder();
    let response = "";
    while (true) {
      const res = await reader.read();
      if (res.done) {
        console.log("Stream done, socket connection has been closed.");
        break;
      }
      response += decoder.decode(res.value);
    }

    return new Response(response);
  }
}