@RestrictedApi(explanation = "Should only be called in tests", link = "",
      allowedOnPath = ".*/src/test/.*")
  public Map<ReplicationQueueId, Map<String, NavigableSet<String>>> getWALs() {
    return Collections.unmodifiableMap(walsById);
  }
Get a copy of the wals of the normal sources on this rs
@return a sorted set of wal names
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java