Empty PSK_ID

[jvermillard]

I tried this simple example with current main branch:

import { fail } from 'k6';
import { setTimeout } from "k6/x/timers"
import { Client } from 'k6/x/coap';


export default function() {
	try {
		// Create new client and connect.
        	let client = new Client(
			"localhost:5684",
			"Client_identity",
			"secretPSK",
			// path/to/client/crt.pem,
			// path/to/client/key.pem,
		);

		// Verify connection.
		let res = client.get("/keep-alive", 10);
		console.log(String.fromCharCode(...res.body));
	} catch (e) {
		fail(e);
	}
}

And it resulted in an empty identity in my DTLS exchange: