🐛 RUM Events cease to publish when beforeUnload event is fired

[sukhpreet96]

Describe the bug
When beforeUnload event is fired, the RUM logs cease to publish. beforeUnload displays a browser modal which prompts the user to leave or stay on the page. In browser-sdk code we are already stopping the RUM events. This should not actually stop the RUM events or logs on before Unload but actually it should be on unload.

To Reproduce
Steps to reproduce the behavior:

1. fire beforeUnload event
2. choose to stay on tab
3. RUM events would stop publishing
   Expected behavior
   The RUM events should keep publishing during beforeUnload and they should actually stop on unload event

[sukhpreet96]

Pull request to fix this issue #3033
@BenoitZugmeyer @amortemousque Requesting a kind review please 🙏

[cy-moi]

Hi @sukhpreet96 ,

Thank you for reaching out.

The collection stopping at beforeUnload indeed has some known limitations and we have received your feature request. Yet, unload is not reliable and is deprecated (cf MDN) in favor of pagehide. Hence, we have been looking at different alternatives to beforeUnload or unload to better detect when the page is gone.

Internally, we are having active discussion on this topic and we will keep you updated.

[sukhpreet96]

@cy-moi Thanks for your consideration!
You might be interested in sendBeacon https://developer.mozilla.org/en-US/docs/Web/API/Navigator/sendBeacon, Refer "Avoid unload and beforeunload" section. This looks promising for usecases like this one