void processNetworkPartitionMessage(NetworkPartitionMessage<ID> msg) {
    if (isStopping) {
      return;
    }
    ID sender = msg.getSender();

    final GMSMembershipView<ID> view = getView();
    if (view != null && isJoined) {
      if (view.getMembers().contains(sender)) {
        String str = "Membership coordinator " + msg.getSender()
            + " has declared that a network partition has occurred";
        forceDisconnect(str);
      } else {
        logger.warn("Ignoring the network partition message from a non-member: " + msg.getSender());
      }
    } else {
      logger.debug(
          "Ignoring, the network partition message, likely this message was intended for the previous Membership service... ");
    }
  }
for testing purpose

@param jrm the join response message to process
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/membership/GMSJoinLeave.java