internal XDAmazonBroadcaster(ISerializer serializer, IPublisherService publisherService,
TopicRepository topicRepository)
{
serializer.Requires("serializer").IsNotNull();
publisherService.Requires("publisherService").IsNotNull();
topicRepository.Requires("topicRepository").IsNotNull();
this.serializer = serializer;
this.publisherService = publisherService;
this.topicRepository = topicRepository;
}