public SortedMap<Integer, StringResult<SuffixNode>> getSuffixes() {
        ensureState(State.COMPLETE);
        return this.suffixes;
    }
"Completes" the accumulator, preventing any further changes.

Also performs some final processing on the accumulators state, before
data is read.
common/src/main/java/me/lucko/luckperms/common/cacheddata/type/MetaAccumulator.java