Is your feature request related to a problem or challenge? Please describe what you are trying to do.
Expose ArrowRowGroupWriter outside crate.

It's usefull for write row group when you use API get_column_writers / append_row_group in ArrowWriter implemented in issue #7359

Describe the solution you'd like
Set public ArrowRowGroupWriter and move function memory_size, get_estimated_total_bytes and rows_count from ArrowWriter

Describe alternatives you've considered
N/A

Additional context