Golang - TLS mutual authentication - Dump client certificates

I have TLS server with mutual authentication. I want to dump client certificates if handshake error. I use ErrorLog in http.Server struct, but this logger doesn't get the information about client certificates. I tried to use the VerifyConnection function in tls.Config struct, but it starts after the correct handshake. How can I dump the client certificates(wrong and corrects)?

You could dump the client certificates through tls Conn.ConnectionState after Conn.HandShake as long as the handshake of TLS is done.

Here are code snippets

	config := tls.Config{
		Certificates:       []tls.Certificate{yourServerCert},
		ClientAuth:         tls.RequestClientCert,
		InsecureSkipVerify: true,
	}

	listener, err := tls.Listen("tcp", "localhost:8080", &config)
	if err != nil {
		fmt.Println("server: listen err %+v \n", err)
		return
	}

	conn, err := listener.Accept()
	if err != nil {
		fmt.Println("server: accept err %+v \n", err)
		return
	}

	tlsConn, ok := conn.(*tls.Conn)
	if !ok {
		fmt.Println("server: invalid tls connection")
		return
	}

	if err := tlsConn.Handshake(); err != nil {
		fmt.Println("server: client handshake err %+v \n", err)
		return
	}

	state := tlsConn.ConnectionState()
	for _, v := range state.PeerCertificates {
		fmt.Printf("server: remote client cert %+v \n", v)
	}