private static void SetResponseHeaders(HttpResponse response, CacheItem item, TimeSpan cacheDuration,
WebCompressionKind compressionKind) {
response.ShouldNotBeNull("response");
response.AppendHeader("Content-Length", item.Data.Length.ToString());
response.ContentType = item.ContentType;
if(item.IsCompressed)
response.AppendHeader("Content-Encoding", compressionKind.ToString().ToLower());
var cache = response.Cache;
// NOTE : HTTPS 에서도 동작하기 위해
cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
cache.SetCacheability(HttpCacheability.Public);
// Cache Expiration 설정
cache.SetExpires(DateTime.Now.ToUniversalTime().Add(cacheDuration));
cache.SetMaxAge(cacheDuration);
cache.SetAllowResponseInBrowserHistory(true);
}