@Override
  public GetReplicationPeerStateResponse isReplicationPeerEnabled(RpcController controller,
    GetReplicationPeerStateRequest request) throws ServiceException {
    boolean isEnabled;
    try {
      isEnabled = server.getReplicationPeerManager().getPeerState(request.getPeerId());
    } catch (ReplicationException ioe) {
      throw new ServiceException(ioe);
    }
    return GetReplicationPeerStateResponse.newBuilder().setIsEnabled(isEnabled).build();
  }
Determines if there is a coprocessor implementation in the provided argument which extends or
implements the provided {@code service}.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java