private void ReadMessage()
        {
            var cont = (string)listView.SelectedItem;

            ChangeStatusContact(cont);
            if (UnreadMessages.Contains(cont))
            {
                UnreadMessages.Remove(cont);
            }
        }
 public Task SendMessage(BaseMessage message)
 {
     if (_isActive)
     {
         UnreadMessages.Add(message);
         NewMessageReceived(this, message);
         UnreadMessages.Remove(message);
         ReadMessages.Add(message);
     }
     return(Task.CompletedTask);;
 }