public async Task MarkRead()
        {
            if (!Messages.Any())
            {
                return;
            }

            var ts = (Messages[0].Ts + 1).ToString();

            if (ChannelId.StartsWith("D"))
            {
                await _slackClient.MarkImChannel(ChannelId, ts);
            }
            else
            {
                await _slackClient.MarkChannel(ChannelId, ts);
            }
        }