Added DBSqlRows and DBSQLArrowBatchIterator public interfaces.
Added arrowRecordIterator which implements DBSQLArrowBatchIterator.
Moved closing the database operation from rows type into resultPageIterator as well as properties that are only used by resultPageIterator.
Added GetArrowBatches function to rows and arrowRowScanner types.
Added HasNext function to BatchIterator and SparkArrowBatch interfaces.
Added example for accessing Arrow batches and updated doc.go
Added DBSqlRows and DBSQLArrowBatchIterator public interfaces. Added arrowRecordIterator which implements DBSQLArrowBatchIterator. Moved closing the database operation from rows type into resultPageIterator as well as properties that are only used by resultPageIterator. Added GetArrowBatches function to rows and arrowRowScanner types. Added HasNext function to BatchIterator and SparkArrowBatch interfaces. Added example for accessing Arrow batches and updated doc.go