System.Net.Mail.SmtpConnection.SetContextAndTryAuthenticate C# (CSharp) Method

        private Authorization SetContextAndTryAuthenticate(ISmtpAuthenticationModule module, NetworkCredential credential, ContextAwareResult context)
        {
            // We may need to restore user thread token here
            if (ReferenceEquals(credential, CredentialCache.DefaultNetworkCredentials))
            {
#if DEBUG
                if (context != null && !context.IdentityRequested)
                {
                    NetEventSource.Fail(this, "Authentication required when it wasn't expected.  (Maybe Credentials was changed on another thread?)");
                }
#endif

                try
                {
                    ExecutionContext x = context == null ? null : context.ContextCopy;
                    if (x != null)
                    {
                        AuthenticateCallbackContext authenticationContext =
                            new AuthenticateCallbackContext(this, module, credential, _client.TargetName, _channelBindingToken);

                        ExecutionContext.Run(x, s_AuthenticateCallback, authenticationContext);
                        return authenticationContext._result;
                    }
                    else
                    {
                        return module.Authenticate(null, credential, this, _client.TargetName, _channelBindingToken);
                    }
                }
                catch
                {
                    // Prevent the impersonation from leaking to upstack exception filters.
                    throw;
                }
            }

            return module.Authenticate(null, credential, this, _client.TargetName, _channelBindingToken);
        }

            void Authenticate() //8
            {
                //if no credentials were supplied, try anonymous
                //servers don't appear to anounce that they support anonymous login.
                if (connection.credentials != null)
                {
                    while (++currentModule < connection.authenticationModules.Length)
                    {
                        //only authenticate if the auth protocol is supported
                        ISmtpAuthenticationModule module = connection.authenticationModules[currentModule];
                        if (!connection.AuthSupported(module))
                        {
                            continue;
                        }

                        NetworkCredential credential = connection.credentials.GetCredential(host, port, module.AuthenticationType);
                        if (credential == null)
                        {
                            continue;
                        }
                        Authorization auth = connection.SetContextAndTryAuthenticate(module, credential, m_OuterResult);

                        if (auth != null && auth.Message != null)
                        {
                            IAsyncResult result = AuthCommand.BeginSend(connection, connection.authenticationModules[currentModule].AuthenticationType, auth.Message, authenticateCallback, this);
                            if (!result.CompletedSynchronously)
                            {
                                return;
                            }

                            LineInfo info = AuthCommand.EndSend(result);

                            if ((int)info.StatusCode == 334)
                            {
                                authResponse = info.Line;
                                if (!AuthenticateContinue())
                                {
                                    return;
                                }
                            }
                            else if ((int)info.StatusCode == 235)
                            {
                                module.CloseContext(connection);
                                connection.isConnected = true;
                                break;
                            }
                        }
                    }

                    //try anonymous if didn't authenticate
                    //if (!connection.isConnected) {
                    //    throw new SmtpException(SR.GetString(SR.SmtpAuthenticationFailed));
                    // }
                }

                connection.isConnected = true;
                InvokeCallback();
            }