public Mono<Void> registerMember(Member member) {
        boolean noClusterId = member.getClusterId() == null;
        boolean noNodeId = member.getNodeId() == null;
        if (noClusterId) {
            if (noNodeId) {
                return Mono.error(new IllegalArgumentException(
                        "Failed to register the member ("
                                + member
                                + ") because both the cluster ID and the node ID are missing"));
            } else {
                return Mono.error(new IllegalArgumentException(
                        "Failed to register the member ("
                                + member
                                + ") because the cluster ID is missing"));
            }
        } else if (noNodeId) {
            return Mono.error(new IllegalArgumentException(
                    "Failed to register the member ("
                            + member
                            + ") because the node ID is missing"));
        }
        return sharedConfigService.insert(member)
                .then();
    }
@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