code: func isTransientConnectionError(err error) bool {
  	urlError, ok := err.(*url.Error)
  	if !ok {
  		return false
  	}
  	opError, ok := urlError.Err.(*net.OpError)
  	if !ok {
  		return false
  	}
  	errno, ok := opError.Err.(syscall.Errno)
  	if !ok {
  		return false
  	}
  	return errno == syscall.ECONNREFUSED || errno == syscall.ECONNRESET
  }
docs: // isTransientConnectionError checks whether given error is "Connection refused" or
  // "Connection reset" error which usually means that apiserver is temporarily
  // unavailable.