func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error) {
	fail := func(err error) (Certificate, error) { return Certificate{}, err }
	var cert Certificate
	var skippedBlockTypes []string
	for {
		var certDERBlock *pem.Block
		certDERBlock, certPEMBlock = pem.Decode(certPEMBlock)
		if certDERBlock == nil {
			break
		}
		if certDERBlock.Type == "CERTIFICATE" {
			cert.Certificate = append(cert.Certificate, certDERBlock.Bytes)
		} else {
			skippedBlockTypes = append(skippedBlockTypes, certDERBlock.Type)
		}
	}
	if len(cert.Certificate) == 0 {
		if len(skippedBlockTypes) == 0 {
			return fail(errors.New("tls: failed to find any PEM data in certificate input"))
		}
		if len(skippedBlockTypes) == 1 && strings.HasSuffix(skippedBlockTypes[0], "PRIVATE KEY") {
			return fail(errors.New("tls: failed to find certificate PEM data in certificate input, but did find a private key; PEM inputs may have been switched"))
		}
		return fail(fmt.Errorf("tls: failed to find \"CERTIFICATE\" PEM block in certificate input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
	}
	skippedBlockTypes = skippedBlockTypes[:0]
	var keyDERBlock *pem.Block
	for {
		keyDERBlock, keyPEMBlock = pem.Decode(keyPEMBlock)
		if keyDERBlock == nil {
			if len(skippedBlockTypes) == 0 {
				return fail(errors.New("tls: failed to find any PEM data in key input"))
			}
			if len(skippedBlockTypes) == 1 && skippedBlockTypes[0] == "CERTIFICATE" {
				return fail(errors.New("tls: found a certificate rather than a key in the PEM for the private key"))
			}
			return fail(fmt.Errorf("tls: failed to find PEM block with type ending in \"PRIVATE KEY\" in key input after skipping PEM blocks of the following types: %v", skippedBlockTypes))
		}
		if keyDERBlock.Type == "PRIVATE KEY" || strings.HasSuffix(keyDERBlock.Type, " PRIVATE KEY") {
			break
		}
		skippedBlockTypes = append(skippedBlockTypes, keyDERBlock.Type)
	}
	x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
	if err != nil {
		return fail(err)
	}
	cert.PrivateKey, err = parsePrivateKey(keyDERBlock.Bytes)
	if err != nil {
		return fail(err)
	}
	switch pub := x509Cert.PublicKey.(type) {
	case *rsa.PublicKey:
		priv, ok := cert.PrivateKey.(*rsa.PrivateKey)
		if !ok {
			return fail(errors.New("tls: private key type does not match public key type"))
		}
		if pub.N.Cmp(priv.N) != 0 {
			return fail(errors.New("tls: private key does not match public key"))
		}
	case *ecdsa.PublicKey:
		priv, ok := cert.PrivateKey.(*ecdsa.PrivateKey)
		if !ok {
			return fail(errors.New("tls: private key type does not match public key type"))
		}
		if pub.X.Cmp(priv.X) != 0 || pub.Y.Cmp(priv.Y) != 0 {
			return fail(errors.New("tls: private key does not match public key"))
		}
	default:
		return fail(errors.New("tls: unknown public key algorithm"))
	}
	return cert, nil
}
X509KeyPair parses a public/private key pair from a pair of
PEM encoded data. On successful return, Certificate.Leaf will be nil because
the parsed form of the certificate is not retained.
package qtls
import (
	"crypto"
	"crypto/ecdsa"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"errors"
	"fmt"
	"io/ioutil"
	"net"
	"strings"
	"time"
)
func Server(conn net.Conn, config *Config) *Conn {
	return &Conn{conn: conn, config: config}
}
func Client(conn net.Conn, config *Config) *Conn {
	return &Conn{conn: conn, config: config, isClient: true}
}
type listener struct {
	net.Listener
	config *Config
}
func (l *listener) Accept() (net.Conn, error) {
	c, err := l.Listener.Accept()
	if err != nil {
		return nil, err
	}
	return Server(c, l.config), nil
}
func NewListener(inner net.Listener, config *Config) net.Listener {
	l := new(listener)
	l.Listener = inner
	l.config = config
	return l
}
func Listen(network, laddr string, config *Config) (net.Listener, error) {
	if config == nil || (len(config.Certificates) == 0 && config.GetCertificate == nil) {
		return nil, errors.New("tls: neither Certificates nor GetCertificate set in Config")
	}
	l, err := net.Listen(network, laddr)
	if err != nil {
		return nil, err
	}
	return NewListener(l, config), nil
}
type timeoutError struct{}
func (timeoutError) Error() string   { return "tls: DialWithDialer timed out" }
func (timeoutError) Timeout() bool   { return true }
func (timeoutError) Temporary() bool { return true }
func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) {
	timeout := dialer.Timeout
	if !dialer.Deadline.IsZero() {
		deadlineTimeout := time.Until(dialer.Deadline)
		if timeout == 0 || deadlineTimeout < timeout {
			timeout = deadlineTimeout
		}
	}
	var errChannel chan error
	if timeout != 0 {
		errChannel = make(chan error, 2)
		time.AfterFunc(timeout, func() {
			errChannel <- timeoutError{}
		})
	}
	rawConn, err := dialer.Dial(network, addr)
	if err != nil {
		return nil, err
	}
	colonPos := strings.LastIndex(addr, ":")
	if colonPos == -1 {
		colonPos = len(addr)
	}
	hostname := addr[:colonPos]
	if config == nil {
		config = defaultConfig()
	}
	if config.ServerName == "" {
		c := config.Clone()
		c.ServerName = hostname
		config = c
	}
	conn := Client(rawConn, config)
	if timeout == 0 {
		err = conn.Handshake()
	} else {
		go func() {
			errChannel <- conn.Handshake()
		}()
		err = <-errChannel
	}
	if err != nil {
		rawConn.Close()
		return nil, err
	}
	return conn, nil
}
func Dial(network, addr string, config *Config) (*Conn, error) {
	return DialWithDialer(new(net.Dialer), network, addr, config)
}
func LoadX509KeyPair(certFile, keyFile string) (Certificate, error) {
	certPEMBlock, err := ioutil.ReadFile(certFile)
	if err != nil {
		return Certificate{}, err
	}
	keyPEMBlock, err := ioutil.ReadFile(keyFile)
	if err != nil {
		return Certificate{}, err
	}
	return X509KeyPair(certPEMBlock, keyPEMBlock)
}