public ReplicationPeerImpl getPeer(String peerId) {
    return peerCache.get(peerId);
  }
Returns the ReplicationPeerImpl for the specified cached peer. This ReplicationPeer will
continue to track changes to the Peer's state and config. This method returns null if no peer
has been cached with the given peerId.
@param peerId id for the peer
@return ReplicationPeer object
hbase-replication/src/main/java/org/apache/hadoop/hbase/replication/ReplicationPeers.java