presto-main/src/main/java/io/prestosql/operator/aggregation/histogram/LegacyHistogramGroupState.java/LegacyHistogramGroupState/LegacyHistogramGroupState
class LegacyHistogramGroupState:    public LegacyHistogramGroupState(Type keyType, int expectedEntriesCount)
    {
        this.keyType = keyType;
        this.expectedEntriesCount = expectedEntriesCount;
    }