Is there a way to start / end an HKWorkoutSession?

[kamarmack]

My app has guided workout routines. Is there a way to 1) start / end an HKWorkoutSession and pass some metadata about the HKWorkoutActivityType, e.g. high intensity interval training? I would attach this callback to my "Get Started" and "End Session" buttons.

From what I understand about the getSample() and setObserver() docs these only provide read access to the user's HKWorkoutSessions that they initiate through the native Activity app. Thanks.