private Counter getWholeDcPastDueCounter(RouterOperation routerOperation) {
    Counter pastDueCounter;
    switch (routerOperation) {
      case GetBlobInfoOperation:
        pastDueCounter = routerMetrics.getBlobInfoPastDueCount;
        break;
      case GetBlobOperation:
        pastDueCounter = routerMetrics.getBlobPastDueCount;
        break;
      case PutOperation:
        pastDueCounter = routerMetrics.putBlobPastDueCount;
        break;
      default:
        throw new IllegalArgumentException("Unsupported router operation when getting whole DC past due counter.");
    }
    return pastDueCounter;
  }
Get certain whole DC past due counter based on given arguments.
@param routerOperation the {@link RouterOperation} that uses this tracker.
@return whole DC past due counter.
ambry-router/src/main/java/com/github/ambry/router/AdaptiveOperationTracker.java