# File lib/new_relic/agent/instrumentation/curb.rb, line 125
      def hook_pending_request(request) #THREAD_LOCAL_ACCESS
        wrapped_request, wrapped_response = wrap_request(request)

        segment = NewRelic::Agent::Transaction.start_external_request_segment(
          wrapped_request.type, wrapped_request.uri, wrapped_request.method)

        segment.add_request_headers wrapped_request

        unless request._nr_instrumented
          install_header_callback(request, wrapped_response)
          install_completion_callback(request, wrapped_response, segment)
          request._nr_instrumented = true
        end
      rescue => err
        NewRelic::Agent.logger.error("Untrapped exception", err)
      end