public Mono<Boolean> hasOneSidedRelationship(
            @NotNull Long ownerId,
            @NotNull Long relatedUserId) {
        try {
            Validator.notNull(ownerId, "ownerId");
            Validator.notNull(relatedUserId, "relatedUserId");
            Validator.notEquals(ownerId,
                    relatedUserId,
                    "The owner ID must not equal to the related user ID");
        } catch (ResponseException e) {
            return Mono.error(e);
        }
        UserRelationship.Key key = new UserRelationship.Key(ownerId, relatedUserId);
        return userRelationshipRepository.existsById(key);
    }
The method exists for backward compatibility
turms-service/src/main/java/im/turms/service/domain/user/service/UserRelationshipService.java