[ARROW-6971] [Rust] Replace "RecordBatchReader" with "BatchIterator"

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Not A Bug
• Affects Version/s: 0.15.0
• Component/s: Rust, Rust - DataFusion
• External issue URL: https://github.com/apache/arrow/issues/23287
• Assignee: Paddy Horan
• Reporter: Paddy Horan
• Created: 23/Oct/19 02:38
• Updated: 11/Jan/23 07:50
• Resolved: 23/Oct/19 16:32

Description

As part of the recent reader work we introduced 

// arrow::record_batch::RecordBatchReader

but in datafusion we have

// datafusion::physical_plan::BatchIterator

These two trait are almost identical (BatchIterator implements Send + Sync whereas RecordBatchReader does not).  I propose we replace RecordBatchReader with BatchIterator (i.e. move it to arrow as it's generally useful outside of datafusion) and update parquet and data fusion accordingly.

andygrove liurenjie1024 do you see any issues with this?