def extract_stored_fields(doc, stored_fields) 
      data = {} 
      unless stored_fields.nil?
        logger.debug "extracting stored fields #{stored_fields.inspect} from document #{doc[:class_name]} / #{doc[:id]}"
        fields = index_definition[:ferret_fields] 
        stored_fields.each do |field|
          if field_cfg = fields[field]
            data[field_cfg[:via]] = doc[field]
          end
        end
        logger.debug "done: #{data.inspect}"
      end
      return data 
    end
def extract_stored_fields(doc, stored_fields) 
      data = {} 
      unless stored_fields.nil?
        logger.debug "extracting stored fields #{stored_fields.inspect} from document #{doc[:class_name]} / #{doc[:id]}"
        fields = index_definition[:ferret_fields] 
        stored_fields.each do |field|
          if field_cfg = fields[field]
            data[field_cfg[:via]] = doc[field]
          end
        end
        logger.debug "done: #{data.inspect}"
      end
      return data 
    end
loads data for fields declared as :lazy from the Ferret document