copyLoop without sync.WaitGroup

	"net/url"

	"os"

	"path"

	"sync"

	"syscall"

	"gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/goptlib"

}

func copyLoop(a net.Conn, b net.Conn) error {

	firstErr := func(errors ...error) error {

		for _, err := range errors {

			if err != nil {

				return err

			}

		}

		return nil

	}

	// Note: b is always the pt connection.  a is the SOCKS/ORPort connection.

	errChan := make(chan error, 2)

	var wg sync.WaitGroup

	wg.Add(2)

	errChan := make(chan error, 1)

	go func() {

		defer wg.Done()

		defer b.Close()

		defer a.Close()

		_, err := io.Copy(b, a)

		errChan <- err

	}()

	go func() {

		defer wg.Done()

		defer a.Close()

		defer b.Close()

	_, err := io.Copy(a, b)

		errChan <- err

	}()

	// Wait for both upstream and downstream to close.  Since one side

	// terminating closes the other, the second error in the channel will be

	// something like EINVAL (though io.Copy() will swallow EOF), so only the

	// first error is returned.

	wg.Wait()

	if len(errChan) > 0 {

		return <-errChan

	}

	return nil

	return firstErr(<-errChan, err, a.Close(), b.Close())

}

func main() {