@Override
  public ReplicationLoad refreshAndGetReplicationLoad() {
    if (this.replicationLoad == null) {
      return null;
    }
    // always build for latest data
    List<ReplicationSourceInterface> allSources = new ArrayList<>();
    allSources.addAll(this.replicationManager.getSources());
    allSources.addAll(this.replicationManager.getOldSources());
    this.replicationLoad.buildReplicationLoad(allSources, null);
    return this.replicationLoad;
  }
Statistics task. Periodically prints the cache statistics to the log.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/Replication.java