System.Net.FtpControlStream.QueueOrCreateFtpDataStream C# (CSharp) Method

        private PipelineInstruction QueueOrCreateFtpDataStream(ref Stream stream)
        {
            if (_dataSocket == null)
                throw new InternalException();

            //
            // Re-entered pipeline with completed read on the TlsStream
            //
            if (_tlsStream != null)
            {
                stream = new FtpDataStream(_tlsStream, (FtpWebRequest)_request, IsFtpDataStreamWriteable());
                _tlsStream = null;
                return PipelineInstruction.GiveStream;
            }

            NetworkStream networkStream = new NetworkStream(_dataSocket, true);

            if (UsingSecureStream)
            {
                FtpWebRequest request = (FtpWebRequest)_request;

                TlsStream tlsStream = new TlsStream(networkStream, _dataSocket, request.RequestUri.Host, request.ClientCertificates);
                networkStream = tlsStream;

                if (_isAsync)
                {
                    _tlsStream = tlsStream;

                    tlsStream.BeginAuthenticateAsClient(s_SSLHandshakeCallback, this);
                    return PipelineInstruction.Pause;
                }
                else
                {
                    tlsStream.AuthenticateAsClient();
                }
            }

            stream = new FtpDataStream(networkStream, (FtpWebRequest)_request, IsFtpDataStreamWriteable());
            return PipelineInstruction.GiveStream;
        }