docs: public void recordCheckoutQueueLength(SocketDestination dest, int queueLength) {
          if(dest != null) {
              getOrCreateNodeStats(dest).recordCheckoutQueueLength(null, queueLength);
              recordCheckoutQueueLength(null, queueLength);
          } else {
              this.checkoutQueueLengthHistogram.insert(queueLength);
              checkMonitoringInterval();
          }
      }