 played an <code>AudioPlayer</code> media source, then played a different Alexa-aware <code>ExternalMediaPlayer</code> media source, such as a deep-linked media app or a local media source, and then manually returned visual activity to the Alexa <code>AudioPlayer</code> GUI. Publishing <code>SetAsForegroundActivity</code> message ensures the next VUI command or GUI interaction with the playback control buttons acts on the <code>AudioPlayer</code> source rather than the more recently played <code>ExternalMed