AD_DATA_READY
Indicate that the ad data response is ready either to support the OnceUX functions or to provide an error indication on why not. Properties included are either error information (VMAP_ERRORS, a String) or data (VMAP_RESPONSE, bound to a VMAP object, and VMAP_TIMELINE, bound to a SparseArray<List<Event>> object associating playhead positions with the event list.)