InternalReadonlyendOptional ReadonlylistenHow long the person listens, for a preview (previewing): the player stops fetching when the playback
has run this long, and the call takes that long (the person's time, which the caller states). Absent,
the download runs to the end of the part the clip needs.
ReadonlyphaseWhether the person is still listening to find the song (previewing: the player is named after the
track's cluster, and its first fragment is fetched before it seeks to the start) or has picked it
(the player is named after the asset and seeks straight to the start).
ReadonlystartWhere the clip starts in the song (audio_asset_start_time_in_ms): the player plays from here.
Readonlytrack
The end of the song the clip needs: the start and the clip's length.