@Nullable
    public Integer getLocalServiceMemberIndex() {
        int index = activeSortedServiceMembers.indexOf(getLocalMember());
        return index != -1
                ? index
                : null;
    }
@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