public Mono<Boolean> isNotBlocked(
            @NotNull Long ownerId,
            @NotNull Long relatedUserId,
            boolean preferCache) {
        return isBlocked(ownerId, relatedUserId, preferCache).map(isBlocked -> !isBlocked);
    }
@return true if a new relationship is created.
turms-service/src/main/java/im/turms/service/domain/user/service/UserRelationshipService.java