Add Heartbeat to websocket connection between Frontend and SignallingServer

[rotor-antoine]

Component your feature request relates to

• Signalling server
• Frontend library
• Frontend UI library
• Matchmaker
• SFU
• This repo

Problem your feature solves? Please describe.
The Frontend Library is not triggering disconnection event when I for instance turn off the wifi of my laptop (which is running the frontend).
Same issue on the Signalling Server. Those kind of "disconnection" wouldn't trigger an event that could be handle by the signalling server .
I know that this repo is not supposed to be necessarily "production ready" but this issue could almost be considered a "bug" as the signalling server will never recover (ie it will never be availalble for a new user) when this type of disconnection with the frontend happen.

Describe the solution you'd like
It seems like a hearbeat check (regular ping messages) both from frontend and from the signalling server, would be able to detect those disconnections:
https://github.com/websockets/ws?tab=readme-ov-file#how-to-detect-and-close-broken-connections

Additional context
Add any other context or screenshots about the feature request here.

[lukehb]

This is a good idea.

I think this is a reasonable suggestion to include in our 5.5 release for the signaling server.

[marospekarik]

This would also fix my problem with cloudfare terminating inactive ws connections after 90s. +1