code: func SafeForLoggingEnv(env []string) []string {
  	newEnv := make([]string, len(env))
  	copy(newEnv, env)
  	for i, entry := range newEnv {
  		parts := strings.SplitN(entry, "=", 2)
  		if !proxyRegex.MatchString(parts[0]) {
  			continue
  		}
  		newVal, _ := SafeForLoggingURL(parts[1])
  		newEnv[i] = fmt.Sprintf("%s=%s", parts[0], newVal)
  	}
  	return newEnv
  }
docs: // SafeForLoggingEnv attempts to strip sensitive information from proxy
  // environment variable strings in key=value form.