code: private void recordSize(MixinMetric mixinMetric, RpcClientLookoutModel model) {
  
          Long requestSize = model.getRequestSize();
          Long responseSize = model.getResponseSize();
  
          if (requestSize != null) {
              DistributionSummary requestSizeDS = mixinMetric.distributionSummary("request_size");
              requestSizeDS.record(model.getRequestSize());
          }
  
          if (responseSize != null) {
              DistributionSummary responseSizeDS = mixinMetric.distributionSummary("response_size");
              responseSizeDS.record(model.getResponseSize());
          }
      }
docs: Record request size and response size
  
  @param mixinMetric MixinMetric
  @param model       information model