Today my kids where watching something from my Kodi device, while at the same time I would have liked to play some music to a UPnP renderer. “It would be nice to tell Symfonium to force playback from the offline cache now”, I thought. But this might be a too rare use case, right? 
I don’t see the correlation, if the Kodi is on it can do both without any issue.
Oh really? I thought it could only play one thing at a time.
But thinking about it, not Kodi would have played, but Symfonium + the UPnP device… makes sense 
Yes Kodi just serve the file and it can serve while playing.