presto-redis/src/main/java/io/prestosql/plugin/redis/RedisRecordCursor.java/RedisRecordCursor/advanceNextPosition
class RedisRecordCursor:    @Override
    public boolean advanceNextPosition()
    {
        while (!keysIterator.hasNext()) {
            if (!hasUnscannedData()) {
                return endOfData();
            }
            fetchKeys();
        }

        return nextRow(keysIterator.next());
    }