Get the number of historical points in this event. These are movements that
have occurred between this event and the previous event. This only applies
to AMOTION_EVENT_ACTION_MOVE events -- all other actions will have a size of 0.
Historical samples are indexed from oldest to newest.
Get the number of historical points in this event. These are movements that have occurred between this event and the previous event. This only applies to AMOTION_EVENT_ACTION_MOVE events -- all other actions will have a size of 0. Historical samples are indexed from oldest to newest.