public ApplicationCorsRule(XElement element)
{
if (element == null) throw new ArgumentNullException(nameof(element));
AllowedOrigins = element.Element("allowed-origins").Value;
AllowedVerbs = element.Element("allowed-methods").Value;
AllowedHeaders = element.Element("allowed-headers").Value;
ExposedHeaders = element.Element("exposed-headers").Value;
MaxAgeSeconds = int.Parse(element.Element("max-age-seconds").Value);
}