mqtt.js client causes event loop to stop

[jeffcrouse]

Describe the bug As soon as I connect to an MQTT broker, the event loop stops running and/or becomes very unpredictable.

To Reproduce Steps to reproduce the behavior:

1. Clone the nodegui-starter as described in the Quick Start Guide
2. npm install @nodegui/nodegui@latest --save
3. Add a loop to update one of the labels every second

async function loop() {
	while(true) {
		const timestamp = Math.floor(+new Date() / 1000);
		label.setText( `Timestamp: ${timestamp.toString()}` );
		await new Promise(resolve => setTimeout(resolve, 1000));
	}
}
loop();

4. npm start
5. Everything works as expected. Woo!
6. install mqtt module, connect to MQTT server

import * as mqtt from 'mqtt';
mqtt.connect('mqtt://localhost:1883');

7. Add a button listener, just in case this is related to #864 button.addEventListener('clicked',(checked)=>console.log("clicked"));
8. The loop executes once, but then gets stuck. Even if I click the button.

Expected behavior The label should continue to be updated every second, even with a MQTT client present.

Desktop (please complete the following information):

• OS: Windows
• NodeGUI version: 0.62.0
• OS Version: Windows 11

Additional Context I've tried various other ways of pausing execution, including not using Promises or setTimeout, but this usually ends up freezing the QWindow altogether, resulting in a white, empty window.

[sedwards2009]

Do you know if mqtt.js works ok in a pure nodejs context? Do timers etc fire correctly when using mqtt.js from node? Can we be sure that mqtt.js is actually returning to the event loop and not spinning some how?

[jeffcrouse]

@sedwards2009 I have used mqtt.js in nodejs for weeks now on my current project with no unexpected results. If there are particular tests that would give you more specific information, I'd be happy to do them.