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

        private void ConnectCallback(IAsyncResult result)
        {
            if (NetEventSource.IsEnabled) NetEventSource.Enter(this);
            try
            {
                _transport.EndGetConnection(result);
                if (_cancelled)
                {
                    Complete(null, result);
                }
                else
                {
                    // Detected durring Begin/EndGetConnection, restrictable using DeliveryFormat
                    bool allowUnicode = IsUnicodeSupported();
                    ValidateUnicodeRequirement(_message, _recipients, allowUnicode);
                    _transport.BeginSendMail(_message.Sender ?? _message.From, _recipients,
                        _message.BuildDeliveryStatusNotificationString(), allowUnicode,
                        new AsyncCallback(SendMailCallback), result.AsyncState);
                }
            }
            catch (Exception e)
            {
                Complete(e, result);
            }
            finally
            {
                if (NetEventSource.IsEnabled) NetEventSource.Exit(this);
            }
        }