public static string ToHttpHeader(this CacheControlScope responseCacheType)
 => responseCacheType == CacheControlScope.Public ? "public" : "private";
 public CacheControlPayload(int maxAge, CacheControlScope scope)
 {
     MaxAge = maxAge;
     Scope  = scope;
 }
 public CacheControlAttribute(int maxAge, CacheControlScope scope = CacheControlScope.Public) : base(MetadataKey, new CacheControlPayload(maxAge, scope))
 {
 }