compactedIds

All ids that have been garbage-collected by any RgaOp.Compact in this op-log — the unbounded half of the compaction record, as against the O(authors) compactedBelow floor.

Public because a consumer that partitions the op-log across storage segments has to decide whether a segment is fully superseded before it may drop it, and suppression comes from the two together: a dot is suppressed iff compactedBelow contains it or its id is in this set. Reading only the floor would judge a foreign author's windowed-away element unsuppressed — dropWindow can never fold a foreign dot into the floor — and so keep its segment on disk forever.

Fugue.compactedIds is public for the same reason and is kept at the same visibility on purpose (#2223) — the two op-log CRDTs are meant to be interchangeable behind OpLogCrdt, so a consumer that swaps one for the other must not hit a wall here.