docs: private void checkRateLimit(String quotaKey, Tracked trackedOp) {
          String quotaValue = null;
          try {
              if(!metadataStore.getQuotaEnforcingEnabledUnlocked()) {
                  return;
              }
              quotaValue = quotaStore.cacheGet(quotaKey);
              // Store may not have any quotas
              if(quotaValue == null) {
                  return;
              }
              // But, if it does
              float currentRate = getThroughput(trackedOp);
              float allowedRate = Float.parseFloat(quotaValue);
              // TODO the histogram should be reasonably accurate to do all
              // these things.. (ghost qps and all)
  
              // Report the current quota usage level
              quotaStats.reportQuotaUsed(trackedOp, Utils.safeGetPercentage(currentRate, allowedRate));
  
              // check if we have exceeded rate.
              if(currentRate > allowedRate) {
                  quotaStats.reportRateLimitedOp(trackedOp);
                  throw new QuotaExceededException("Exceeded rate limit for " + quotaKey
                                                   + ". Maximum allowed : " + allowedRate
                                                   + " Current: " + currentRate);
              }
          } catch(NumberFormatException nfe) {
              // move on, if we cannot parse quota value properly
              logger.debug("Invalid formatting of quota value for key " + quotaKey + " : "
                           + quotaValue);
          }
      }