code: func formatBuckets(hg *statistics.Histogram, lowBkt, highBkt, idxCols int) string {
  	if lowBkt == highBkt {
  		return hg.BucketToString(lowBkt, idxCols)
  	}
  	if lowBkt+1 == highBkt {
  		return fmt.Sprintf("%s, %s", hg.BucketToString(lowBkt, 0), hg.BucketToString(highBkt, 0))
  	}
  	// do not care the middle buckets
  	return fmt.Sprintf("%s, (%d buckets, total count %d), %s", hg.BucketToString(lowBkt, 0),
  		highBkt-lowBkt-1, hg.Buckets[highBkt-1].Count-hg.Buckets[lowBkt].Count, hg.BucketToString(highBkt, 0))
  }
docs: // formatBuckets formats bucket from lowBkt to highBkt.