public void LogViewerLastSeen(string username)
 {
     if (ViewersLastSeenDate.ContainsKey(username))
     {
         ViewersLastSeenDate[username] = DateTime.Now.ToFileTime();
     }
     else
     {
         ViewersLastSeenDate.Add(username, DateTime.Now.ToFileTime());
     }
 }
 public bool IsViewerInLastSeenList(string username)
 {
     return(ViewersLastSeenDate.ContainsKey(username));
 }