code: def run_user_block(extractor, response, body, &block)
        header = extractor.extract_header_data(response)
        case block.arity
          when 1 then yield(header)
          when 2 then yield(header, body)
          else
            raise AdsCommon::Errors::ApiException,
                "Wrong number of block parameters: %d" % block.arity
        end
        return nil
      end
docs: Yields to user-specified block with additional information such as
   headers.