For the time being, we still assume that the row versions vector
is *nearly* sorted, so we just perform a linear reverse search
and insert the version at an appropriate place.
During concurrency tests, the error was at most 1 offset,
and as long as we empirically prove it to be below a reasonable
constant, we're fine. Otherwise we should consider switching
to either a data structure that keeps elements ordered,
or at least a list that gives us constant insertion.