import { createServer } from "node:http"
import { once } from "node:events"
import { RetryAgent, Agent, fetch } from "undici";
import asserts from "node:assert";

let retry = true;
const server = createServer((req, res) => {
  res.writeHead(200, { "Content-Type": "text/plain" });
	if (retry) {
		retry = false;
		res.flushHeaders();
		res.write('H');
		setTimeout(() => {
			res.end('ello World');
		}, 1000);
	} else {
		res.end('Hello World');
	}
})

server.listen();
await once(server, 'listening')

const agent = new RetryAgent(new Agent({bodyTimeout: 500}), {
	errorCodes: ['UND_ERR_BODY_TIMEOUT'],
});
const { port } = server.address()
const res = await fetch(`http://localhost:${port}`, {
    dispatcher: agent,
});
asserts.equal(await res.text(), 'Hello World');

server.close();

AssertionError [ERR_ASSERTION]: 'HHello World' == 'Hello World'