MusicFlow
Implementation: Sylvain Rebaud, Alexandre Brouaux
MusicFlow is the only iOS app that can stream any music service to an Xbox or any other DLNA compatible devices. Supported music services include Apple Music, Pandora, Spotify, Rdio, etc…
By making a compatible DLNA device appear as an Airplay device, you can directly select it using the standard AirPlay picker on iOS.