playableContentManagerInitializePlaybackQueueWithContentItemsCompletionHandler
default void playableContentManagerInitializePlaybackQueueWithContentItemsCompletionHandler(MPPlayableContentManager contentManager,
NSArray<?> contentItems,
MPPlayableContentDelegate.Block_playableContentManagerInitializePlaybackQueueWithContentItemsCompletionHandler completionHandler)
This method is called when a media player interface wants the now playing
app to setup a playback queue for later playback. The application should
load content into its play queue based on the provided content items and
prepare it for playback, but not start playback until a Play command is
received or if the playable content manager requests to play something else.
A nil contentItems array means that the app should prepare its queue with
anything it deems appropriate.
The app should call the provided completion handler once it is ready to play
something.