code: public static void registerQueueLengthMetrics(MetricGroup group, ResultPartition partition) {
  		ResultPartitionMetrics metrics = new ResultPartitionMetrics(partition);
  
  		group.gauge("totalQueueLen", metrics.getTotalQueueLenGauge());
  		group.gauge("minQueueLen", metrics.getMinQueueLenGauge());
  		group.gauge("maxQueueLen", metrics.getMaxQueueLenGauge());
  		group.gauge("avgQueueLen", metrics.getAvgQueueLenGauge());
  	}
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