Player.PlaybackSuppressionReason (ExoPlayer library)

```
@Documented
@Retention(SOURCE)
@Target({FIELD,METHOD,PARAMETER,LOCAL_VARIABLE,TYPE_USE})
public static @interface Player.PlaybackSuppressionReason
```
Reason why playback is suppressed even though Player.getPlayWhenReady() is true. One of Player.PLAYBACK_SUPPRESSION_REASON_NONE, Player.PLAYBACK_SUPPRESSION_REASON_TRANSIENT_AUDIO_FOCUS_LOSS or Player.PLAYBACK_SUPPRESSION_REASON_UNSUITABLE_AUDIO_ROUTE.