def write_csv(file_name, records)
      line_number = exporter.connection_adapter.write(local_file(file_name), records)
    end
def write_csv(file_name, records)
      line_number = exporter.connection_adapter.write(local_file(file_name), records)
    end
Writes all results to one file for future splitting.
 @param file_name [String] name of the local export file
 @return [Integer] number of records to export.