@Override
  public String toString() {
    return String.format("%d/%d (%.2f%%)", currentCompactedKVs, getTotalCompactingKVs(),
      100 * getProgressPct());
  }
Returns the total data size processed by the currently running compaction, in bytes
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/compactions/CompactionProgress.java