how to get mail delivery report in asp.net

public void mail()
   {
       System.Net.Mail.MailMessage mail = new System.Net.Mail.MailMessage();
       System.Net.Mail.SmtpClient smtpClient = new SmtpClient();
         
        //set the addresses
       mail.From = new MailAddress("xyz@gmail.com");
       mail.To.Add(TextBox1.Text);
       mail.ReplyTo = new MailAddress("xyz@gmail.com");
       //set the content
       mail.Subject = "This is an email";
       mail.Body = "body content of the email.";
 
            
       mail.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;
       mail.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;
       mail.DeliveryNotificationOptions = DeliveryNotificationOptions.Delay;
       mail.DeliveryNotificationOptions = DeliveryNotificationOptions.Never;
       mail.DeliveryNotificationOptions = DeliveryNotificationOptions.None;
         
       mail.Headers.Add("Disposition-Notification-To", "xyz@gmail.com");
 
      smtpClient.Host = "relay-hosting.secureserver.net";
       mail.Priority = System.Net.Mail.MailPriority.High;
       smtpClient.Send(mail);

   }