/// <summary>
/// Destroy a tracker that isn't used.
/// </summary>
/// <param name="tracker">Tracker.</param>
private void EndTracking(InputTracker tracker)
{
tracker.StopTracking();
_trackers.Remove(tracker);
_trackerLookup.Remove(tracker.FingerId);
if (EventReleased != null)
{
EventReleased(tracker);
}
tracker = null;
}