System.Net.FtpWebRequest.AsyncRequestCallback C# (CSharp) Method

        private void AsyncRequestCallback(object obj)
        {
            if (NetEventSource.IsEnabled) NetEventSource.Enter(this, obj);
            RequestStage stageMode = RequestStage.CheckForError;

            try
            {
                FtpControlStream connection;
                connection = obj as FtpControlStream;
                FtpDataStream stream = obj as FtpDataStream;
                Exception exception = obj as Exception;

                bool completedRequest = (obj == null);

                if (NetEventSource.IsEnabled) NetEventSource.Info(this, $"stream:{stream} conn:{connection} exp:{exception} completedRequest:{completedRequest}");
                while (true)
                {
                    if (exception != null)
                    {
                        if (AttemptedRecovery(exception))
                        {
                            connection = CreateConnection();
                            if (connection == null)
                                return;

                            exception = null;
                        }
                        if (exception != null)
                        {
                            SetException(exception);
                            break;
                        }
                    }

                    if (connection != null)
                    {
                        lock (_syncObject)
                        {
                            if (_aborted)
                            {
                                if (NetEventSource.IsEnabled) NetEventSource.Info(this, $"Releasing connect:{connection}");
                                connection.CloseSocket();
                                break;
                            }
                            _connection = connection;
                            if (NetEventSource.IsEnabled) NetEventSource.Associate(this, _connection);
                        }

                        try
                        {
                            stream = (FtpDataStream)TimedSubmitRequestHelper(true);
                        }
                        catch (Exception e)
                        {
                            exception = e;
                            continue;
                        }
                        return;
                    }
                    else if (stream != null)
                    {
                        lock (_syncObject)
                        {
                            if (_aborted)
                            {
                                ((ICloseEx)stream).CloseEx(CloseExState.Abort | CloseExState.Silent);
                                break;
                            }
                            _stream = stream;
                        }

                        stream.SetSocketTimeoutOption(Timeout);
                        EnsureFtpWebResponse(null);

                        stageMode = stream.CanRead ? RequestStage.ReadReady : RequestStage.WriteReady;
                    }
                    else if (completedRequest)
                    {
                        connection = _connection;

                        if (connection != null)
                        {
                            EnsureFtpWebResponse(null);

                            // This to update response status and exit message if any.
                            // Note that the status 221 "Service closing control connection" is always suppressed.
                            _ftpWebResponse.UpdateStatus(connection.StatusCode, connection.StatusLine, connection.ExitMessage);
                        }

                        stageMode = RequestStage.ReleaseConnection;
                    }
                    else
                    {
                        throw new InternalException();
                    }
                    break;
                }
            }
            catch (Exception exception)
            {
                SetException(exception);
            }
            finally
            {
                FinishRequestStage(stageMode);
                if (NetEventSource.IsEnabled) NetEventSource.Exit(this);
            }
        }