public void Initialize(SendRequest sendRequest)
        {
            if (sendRequest.NetworkCredential == null)
            {
                sendRequest.NetworkCredential = new System.Net.NetworkCredential(AppSettingsUtil.GetString("email.username"), AppSettingsUtil.GetString("email.password"));
            }

            var sender = new SmtpSender(() => new SmtpClient(sendRequest.SmtpClientHost)
            {
                EnableSsl      = sendRequest.EnableSsl,
                DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory,
                Credentials    = sendRequest.NetworkCredential
            });

            EmailSend.DefaultSender = sender;
        }