How should I idiomatically represent time intervals (not just durations) in C++?

I like C++11's std::chrono facilities, which let me work with:

• time points
• clocks
• durations (= differences between time points)

but I occasionally need to work with time intervals, i.e. not just the duration between points, but a duration placed in time, i.e. a pair of either (start timepoint, end timepoint) or (start timepoint, duration). Specifically, I'm writing a library which involves exposing such intervals - which I create, i.e. I don't rely on classes for them defined elsewhere.

IIANM, std::chrono does not offer any facilities/machinery for that. So - what is the common idiom for representing such time intervals (in a std::chrono-friendly way), which I might use?

Notes:

• I hope the answer isn't "roll your own class", but if you believe it is, please justify that answer.
• I would hope for an answer valid for C++11 and later, but you may indicate a newer version of the standard as a minimum, if necessary.
• Has @HowardHinnant said anything about this?
• I would like to be able to work with time points from any Clock type (including ones not built in to the standard library) and any Rep type - so that I don't limit the users of my library.

Hinnant's date library doesn't seem to contain this.

As pointed out above, Boost has this, but it uses its ptime type, not Clock and Rep as you prefer.

So the justification for creating your own data structure is just that: what you want doesn't seem to already exist anywhere. It looks easy enough.