Events a PlayerAdapter must support. timedmetadata is capability-style: adapters that
can surface in-stream markers (HLS ID3 / EXT-X-DATERANGE, DASH emsg) emit it per marker.
externalplaybackchange is capability-style too: adapters that can detect AirPlay emit an
ExternalPlaybackChange whenever the content player's external playback state changes.
Events a PlayerAdapter must support.
timedmetadatais capability-style: adapters that can surface in-stream markers (HLS ID3 / EXT-X-DATERANGE, DASH emsg) emit it per marker.externalplaybackchangeis capability-style too: adapters that can detect AirPlay emit an ExternalPlaybackChange whenever the content player's external playback state changes.