code: func httpWithTLS(rootCa, key string) (*http.Client, error) {
  	var client *http.Client
  	certData, err := ioutil.ReadFile(rootCa)
  	if err != nil {
  		return nil, fmt.Errorf("unable to find cert path=%s, error=%v", rootCa, err)
  	}
  	cert := pkcs12ToPem(certData, key)
  	config := &tls.Config{
  		Certificates: []tls.Certificate{cert},
  	}
  	tr := &http.Transport{
  		TLSClientConfig:    config,
  		DisableCompression: true,
  	}
  	client = &http.Client{Transport: tr}
  	return client, nil
  }
docs: //httpWithTLS CA证书