presto-main/src/main/java/io/prestosql/type/setdigest/SetDigestStateFactory.java/SetDigestStateFactory/getEstimatedSize
class SetDigestStateFactory:        @Override
        public long getEstimatedSize()
        {
            if (digest == null) {
                return SIZE_OF_SINGLE;
            }
            return SIZE_OF_SINGLE + digest.estimatedInMemorySize();
        }