Context: you used to be able to cast the full screen on Android and when you locked the phone, it would just keep sending audio. Power usage was surprisingly low, and on a closed network, it's not really a big worry otherwise. Originally I used the Chromecast audio, and then a regular Chromecast with an audio extractor or a Wiim box. Now, when you lock your phone it stops casting. There are other options to get some individual apps to send audio data to the Chromecast with big caveats (Spotify loses track volume normalization, for instance), but nothing if you want everything without having to switch things manually. SonoBus will probably work, but now I need to buy new hardware to run it on if I want it independent of my laptop and running straight into the mixer.