in core/src/main/scala/org/apache/pekko/persistence/r2dbc/internal/BySliceQuery.scala [130:139]
def clearUntil(time: Instant): Buckets = {
val epochSeconds = time.minusSeconds(BucketDurationSeconds).toEpochMilli / 1000
val newCountByBucket = countByBucket.dropWhile { case (key, _) => epochSeconds >= key }
if (newCountByBucket.size == countByBucket.size)
this
else if (newCountByBucket.isEmpty)
new Buckets(immutable.SortedMap(countByBucket.last)) // keep last
else
new Buckets(newCountByBucket)
}