s.moveToNext();
assert s.getCounterId().equals(id2);
assert s.getCount() == 0L;
assert -s.getClock() > now - 1000;
assert -s.getClock() <= now;
s.moveToNext();
assert s.getCounterId().equals(id3);
assert s.getCount() == 12L;
// Then collect old shards
CounterColumn.mergeAndRemoveOldShards(dk, cf, Integer.MAX_VALUE, Integer.MIN_VALUE, false);