public async Task <EmailSendResult> SendAsync(MailMessage message)
        {
            var recipients  = String.Join(";", message.To.Select(msg => msg.Address));
            var senderEmail = $"{message.From.DisplayName} <{message.From.Address}>";

            var templateSendResult = await _client.SendEmailWithTemplateAsync <TSendGridTemplateModel>
                                         (_emailTemplateId,
                                         _emailTemplate,
                                         recipients,
                                         senderEmail);

            return(new EmailSendResult
            {
                IsSuccess = templateSendResult.Status == PostmarkStatus.Success,
                Message = templateSendResult.Message,
                TrackingIdentifier = templateSendResult.MessageID.ToString()
            });
        }