# File lib/new_relic/agent/transaction/external_request_segment.rb, line 49
        def read_response_headers response
          return unless record_metrics? && CrossAppTracing.cross_app_enabled?
          return unless CrossAppTracing.response_has_crossapp_header?(response)
          unless data = CrossAppTracing.extract_appdata(response)
            NewRelic::Agent.logger.debug "Couldn't extract_appdata from external segment response"
            return
          end

          if CrossAppTracing.valid_cross_app_id?(data[0])
            @app_data = data
            update_segment_name
          else
            NewRelic::Agent.logger.debug "External segment response has invalid cross_app_id"
          end
        rescue => e
          NewRelic::Agent.logger.error "Error in read_response_headers", e
        end