Structured workout definition as produced by Intervals.icu (the workout_doc field on
calendar workout events and library workouts). The vendored spec types it as an object
of objects and models nothing further, so it is an open record here; it is never null.
Structured workout definition as produced by Intervals.icu (the
workout_docfield on calendar workout events and library workouts). The vendored spec types it as an object of objects and models nothing further, so it is an open record here; it is never null.