private void OnSendInstantMessageCommandExecute()
        {
            var message = new RelayMessage
            {
                SentDateTimeUtc = DateTimeOffset.UtcNow,
                ToUserId        = UserId,
                FromUserId      = RegistrationSettings.UserId,
                Payload         = InstantMessage.Trim(),
                Tag             = RelayMessageTags.InstantMessage
            };

            InstantMessage = null;
            _clientChannel.Relay(message);
            ((ObservableCollection <InstantMessageViewModel>)InstantMessages).Add(new InstantMessageViewModel
            {
                Body                = message.Payload,
                DeliveredAt         = message.SentDateTimeUtc.LocalDateTime,
                IsSender            = true,
                SenderName          = RegistrationSettings.Name,
                SenderProfileSource = OwnProfileSource
            });
        }