code: func restoreFlash(req *Request) Flash {
  	flash := Flash{
  		Data: make(map[string]string),
  		Out:  make(map[string]string),
  	}
  	if cookie, err := req.Cookie(CookiePrefix + "_FLASH"); err == nil {
  		ParseKeyValueCookie(cookie.GetValue(), func(key, val string) {
  			flash.Data[key] = val
  		})
  	}
  	return flash
  }
docs: // restoreFlash deserializes a Flash cookie struct from a request.