date ranges in events API are vague
Problem to solve
https://docs.gitlab.com/ce/api/events.html#date-formatting does not answer the following questions:
- How are time zones handled?
- If I ask for events "after" Dec 31, 2018, do I see events that happened on December 31? Or only events that happened on Jan 1 or later? Same question for "before".
Proposal
For (2), I don't know what the API actually does, but since the docs don't say, there's the opportunity to change the code if desired. The correct way to deal with this is with half-open intervals -- "after" should be "on or after", while "before" should be "strictly before". This is the same convention that Dijkstra advocates for array ranges, so it's familiar to programmers, and it allows adjacent ranges to easily be defined without date arithmetic -- the "after" of one range is the "before" of the next.