code: func addressFromDeprecatedFlags(addr string, port int32) string {
  	if port == 0 {
  		return ""
  	}
  	return proxyutil.AppendPortIfNeeded(addr, port)
  }
docs: // addressFromDeprecatedFlags returns server address from flags
  // passed on the command line based on the following rules:
  // 1. If port is 0, disable the server (e.g. set address to empty).
  // 2. Otherwise, set the port portion of the config accordingly.