public Feed GetFeed(int numberOfStreams, int activitiesPerStream)
        {
            var feedId = Encoding.UTF8.GetBytes("feedid");
            var feed = feedFactory.GG(feedId);
            for (int i = 0; i < numberOfStreams; i++)
            {
                for (int j = 0; j < activitiesPerStream; j++)
                {
                    var streamId = Guid.NewGuid();
                    var feedStream = new FeedStream(feedId, streamId.ToByteArray());
                    feed.AttachStream(feedStream);
                    var externalId = $"extid-{i}-{j}";
                    var body = new ActivityBody() { Content = externalId };

                    var activity = Activity.UnitTestFactory(streamId.ToByteArray(), Encoding.UTF8.GetBytes(externalId), body, "author", DateTime.UtcNow.AddYears(i));
                    activityRepository.Append(activity);
                }
            }

            return feed;
        }