private static async Task SendAttachmentsMessageAync(ClientMessenger client, string userId)
        {
            using (var stream = File.OpenRead(@"C:\Data\FTP\Ross\hubster.io\work\Sample Attachments\File\pdf-sample.pdf"))
            {
                var result = await client.SendFileAttachmentAsync(userId, stream, "pdf-sample.pdf", "application/pdf", "file");
            }

            using (var stream = File.OpenRead(@"C:\Data\FTP\Ross\hubster.io\work\Sample Attachments\Images\Cosmos.jpg"))
            {
                var result = await client.SendFileAttachmentAsync(userId, stream, "Cosmos.jpg", "image/jpeg", "image");
            }

            using (var stream = File.OpenRead(@"C:\Data\FTP\Ross\hubster.io\work\Sample Attachments\Audio\2647611198313044978-a2002011001_e02.mp3"))
            {
                var result = await client.SendFileAttachmentAsync(userId, stream, "NiceMusic.mp3", "audio/mp3", "audio");
            }

            using (var stream = File.OpenRead(@"C:\Data\FTP\Ross\hubster.io\work\Sample Attachments\video\TextInMotion-Sample-576p.mp4"))
            {
                var result = await client.SendFileAttachmentAsync(userId, stream, "My Video.mp3", "video/mp4", "video");
            }
        }