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

RowFilter is the API used to apply predicates when reading Parquet data.

Although RowFilter itself is public, its predicates are marked as public within the current crate. Today the only way to apply predicates using RowFilter is through ParquetRecordBatchReader or ParquetRecordBatchStreamReader. This prevents some usecases we have to read Parquet data not through ParquetRecordBatchReader or ParquetRecordBatchStreamReader. If we can expose predicates it would help with those special usecases.

Describe the solution you'd like

Mark predicates as public instead of public within the crate.

Describe alternatives you've considered

For us to maintain a forked version of arrow rs which is not ideal.

Additional context

It would be also nice to expose ReadPlanBuilder and ReadPlan as well so that users can construct their own reader instead of relying on ParquetRecordBatchReader or ParquetRecordBatchStreamReader.