Some read routes cut their windows in SQL against the database's now(),
which a pinned Date cannot reach; a walk pinned to a fixed date then reads
less of its record every day the calendar moves on. relativeToAnchor writes
every instant and day key of a snapshot relative to the start of the
current UTC day, so a walk can lay its record out from today and still read
the same snapshot on any day.
The series walk uses it with the clock unpinned; the analytics walk pins
the clock to noon of today, keeps its account in UTC and is re-recorded in
that form (its earlier snapshots proved the builder move before this
change).
Marc-André Bombeck
b2f6c37c37