Set<Path> getLastestPath() {
    synchronized (latestPaths) {
      return Sets.newHashSet(latestPaths.values());
    }
  }
Get the normal source for a given peer
@return the normal source for the give peer if it exists, otherwise null.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java