private void notifyListeners(Map<String, Map<Integer, BrokerRegistration>> main2proxyByRack) {
        listeners.forEach(listener -> {
            try {
                listener.onChange(main2proxyByRack);
            } catch (Throwable e) {
                LOGGER.error("fail to notify listener {}", listener, e);
            }
        });
    }
Get the proxy leader node when NOT_LEADER_OR_FOLLOWER happens.
core/src/main/java/kafka/automq/zerozone/ProxyNodeMapping.java