public async Task <Unit> Handle(UpdateAllergenCommand request, CancellationToken cancellationToken)
        {
            try
            {
                var entity = _mapper.Map <Allergen>(request.Allergen);

                await _repository.Update(entity, cancellationToken);

                _eventBus.Publish(new AllergenUpdatedEvent(request.Allergen));

                return(Unit.Value);
            }
            catch (Exception e)
            {
                throw new UpdateException(request.Allergen.Id, e);
            }
        }