    # File lib/action_controller/request.rb, line 136
        def fresh?(response)
          case
          when if_modified_since && if_none_match
            not_modified?(response.last_modified) && etag_matches?(response.etag)
          when if_modified_since
            not_modified?(response.last_modified)
          when if_none_match
            etag_matches?(response.etag)
          else
            false
          end
        end