presto-cassandra/src/main/java/io/prestosql/plugin/cassandra/CassandraRecordCursor.java/CassandraRecordCursor/advanceNextPosition
class CassandraRecordCursor:    @Override
    public boolean advanceNextPosition()
    {
        if (!rs.isExhausted()) {
            currentRow = rs.one();
            count++;
            return true;
        }
        return false;
    }