OpenVPN interference with Librespot's Spotify Connect feature

[Denio21]

Is your feature request related to a problem? Please describe.
Yes, when using the Librespot's Spotify Connect functionality in conjunction with OpenVPN, there is a problem. Librespot tends to route traffic through the tun interface (related to VPN) instead of the interface that's connected to the LAN. This makes it difficult for Librespot to work seamlessly when a VPN is in use.

Describe the solution you'd like
I'd like Librespot to have a flag or configuration option that allows users to specify which network interface it should use. For instance, a user could set the flag to ensure that Librespot only uses the interface connected to the LAN, bypassing the tun interface associated with the VPN.

Describe alternatives you've considered
One alternative I've looked into is running a network namespace. The idea is that this namespace would, in theory, lock Librespot to a specified network interface. However, having a built-in flag for this in Librespot would be a more straightforward and user-friendly solution. The other alternative is to authenticate with account.

Additional context
When a VPN is active, many applications can default to using the VPN's tun interface. For applications like Librespot, which require local network visibility for features like Spotify Connect, this can cause functionality issues. Having a simple configuration option or flag would help users easily resolve this problem without having to dive into more complex network configurations.

[kingosticks]

For applications like Librespot, which require local network visibility for features like Spotify Connect,

There is already an option for specifying the interface to use for zeroconf. But we are missing an option for the other traffic.