System.Net.WebSockets.WebSocketHandle.ConnectSocketAsync C# (CSharp) Method

        private async Task<Socket> ConnectSocketAsync(string host, int port, CancellationToken cancellationToken)
        {
            IPAddress[] addresses = await Dns.GetHostAddressesAsync(host).ConfigureAwait(false);

            ExceptionDispatchInfo lastException = null;
            foreach (IPAddress address in addresses)
            {
                var socket = new Socket(address.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
                try
                {
                    using (cancellationToken.Register(s => ((Socket)s).Dispose(), socket))
                    using (_abortSource.Token.Register(s => ((Socket)s).Dispose(), socket))
                    {
                        try
                        {
                            await socket.ConnectAsync(address, port).ConfigureAwait(false);
                        }
                        catch (ObjectDisposedException ode)
                        {
                            // If the socket was disposed because cancellation was requested, translate the exception
                            // into a new OperationCanceledException.  Otherwise, let the original ObjectDisposedexception propagate.
                            CancellationToken token = cancellationToken.IsCancellationRequested ? cancellationToken : _abortSource.Token;
                            if (token.IsCancellationRequested)
                            {
                                throw new OperationCanceledException(new OperationCanceledException().Message, ode, token);
                            }
                        }
                    }
                    cancellationToken.ThrowIfCancellationRequested(); // in case of a race and socket was disposed after the await
                    _abortSource.Token.ThrowIfCancellationRequested();
                    return socket;
                }
                catch (Exception exc)
                {
                    socket.Dispose();
                    lastException = ExceptionDispatchInfo.Capture(exc);
                }
            }

            lastException?.Throw();

            Debug.Fail("We should never get here. We should have already returned or an exception should have been thrown.");
            throw new WebSocketException(SR.net_webstatus_ConnectFailure);
        }