API to update data reader column properties when data finishes loading

We need a method to be invoked when DataRowReader finishes loading its data ... this method should have access to reader column properties (read/update). The use case is about updating some column properties that are data dependent after reader finishes execution. 

I need to include row counts in a custom column property. This property needs to be updated after the reader loads all its data ... today we pass the column properties when we create the reader ... this is ok for static column properties that are data independent. But once it comes to adding some data related stats as column properties, we have no solution today.

Having an override method in DataRowReader to invoke when data finishes with read/write access to DataRowReaderColumn collection would be beneficial