public Mono<Long> unregisterMembers(Set<String> nodeIds) {
        Filter filter = Filter.newBuilder(2)
                .eq(Member.ID_CLUSTER_ID, getLocalMember().getClusterId())
                .in(Member.ID_NODE_ID, nodeIds);
        return sharedConfigService.remove(Member.class, filter)
                .map(DeleteResult::getDeletedCount);
    }
@return null if the local node isn't active
turms-server-common/src/main/java/im/turms/server/common/infra/cluster/service/discovery/DiscoveryService.java