How to implement intervals?

[ePaul]

Rule 127 describes intervals (i.e. a range of date-times, with some special open-ended ones), and suggests to use these with ..._between query parameters instead of a pair of ..._before and ..._after query parameters.

In the API guild meeting of 2024-04-16, we found that this is not quite easy to implement, e.g. the standard java.time API doesn't even has a type representing it and Joda time's Interval doesn't support open-ended intervals. Guava's Range<Instant> could work, but needs a manual parser. (Same issue likely exists for other languages.)

We should get a section in the best practices chapter giving some ideas of how to implement this (@tkrop mentioned an example (internal link)), or alternatively rethink this recommendation.