ReadonlyinitialThe initial playback delay between when playback was requested to begin 'play' and the
playing event, in seconds.
IPD is to be reported on termination events,
This should be summed with the time between the user interaction and when the player
play() has been called in order to calculate initialPlaybackDelaySeconds.
https://console.harmony.a2z.com/music-metrics/docs/attribute/initialPlaybackDelayMilliseconds
ReadonlyplaybackThe timestamp of when playback began.
ReadonlyplayThe timestamp of when playback was requested. This will be the timestamp from the initiation
command before playback started, either play or seeking.
Attributes calculated when playback has last started.
Not to be confused with streaming initiated, which represents only the first time playback has started or restarted.