public void AddSessionEvent(string sessionId, EventType type, string senderId, string senderName, IEnumerable <string> recipients, string data)
 {
     using (HistoryRepository repository = this.CreateRepository())
     {
         repository.AddSessionEvent(sessionId, DateTime.UtcNow, type, senderId, senderName, recipients, data);
         if (type == EventType.Joined)
         {
             var participant = new Participant()
             {
                 Id          = Guid.NewGuid().ToString(),
                 ContactId   = senderId.ToString(),
                 ContactName = senderName
             };
             repository.AddParticipant(sessionId, participant);
         }
     }
 }