code: func (t *tracker) end(ctx context.Context, err error) {
  	status := getResponseStatus(err)
  
  	ctx, _ = tag.New(ctx, tag.Upsert(StatusCode, strconv.Itoa(int(status.Code))))
  	stats.Record(ctx, t.profile.LatencyMeasure.M(float64(time.Since(t.startedAt))/float64(time.Millisecond)))
  
  	if t.span != nil {
  		t.span.SetStatus(status)
  		t.span.End()
  	}
  }
docs: // end a request's monitoring session. If there is a span ongoing, it will
  // be ended and metrics will be recorded.