System.Net.Mail.SmtpClient.SendAsync C# (CSharp) Method

        public void SendAsync(string from, string recipients, string subject, string body, object userToken)
        {
            if (_disposed)
            {
                throw new ObjectDisposedException(GetType().FullName);
            }
            SendAsync(new MailMessage(from, recipients, subject, body), userToken);
        }

        public void sendEmail(String targetEmail, String targetName, String targetLogin, String password)
        {
            String body;

            body = "Dear " + targetName + ", \n\n";
            body += "Thank you for using our application! \n";
            body += "Below is your authentication information: \n\n";
            body += "\t Your login: "******"\n";
            body += "\t Your new password: "******"\n\n";
            body += "----------------\n";
            body += "Sincerely, Software Development Team";

            try
            {
                SmtpClient client = new SmtpClient("smtp.gmail.com");
                client.Port = 587;
                client.EnableSsl = true;
                client.Timeout = 100000;
                client.DeliveryMethod = SmtpDeliveryMethod.Network;
                client.UseDefaultCredentials = false;
                client.Credentials = new NetworkCredential(
                  "*****@*****.**", "humber123");
                MailMessage msg = new MailMessage();
                msg.To.Add(targetEmail);
                msg.From = new MailAddress("*****@*****.**");
                msg.Subject = "NEW PASSWORD REQUEST";
                msg.Body = body;
                client.SendAsync(msg, "message");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }