The utility of point-in-time and interval events has become clear
during archetype design analysis of clinically measured phenomena.
To further improve the representation of interval events, we should
optional record how many samples were taken in each interval event
(and/or sample width of original sampling leading to an interval
variance and/or other measures during interval
a way of allowing one interval event to capture samples within +/-
xxx, i.e. outer limits to still call it one event.
to make archetyping clearer, maybe separate out EVENT, POINT_EVENT,