The fastest time over distance; null with no distance, no
timestamps, or when the section is shorter.
The fastest time over each distance (by default 400 m up to the marathon), shortest first. Distances longer than the section are left out. A pool swim searches its lengths, so an effort starts and ends at a length's start or end (or the section's own ends).
Optionaldistances: readonly Distance[]
Best efforts by pace inside a section:
run.pace.bestEffort(km(5)).