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Author: JunTaoLuo

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingContext.cs

@@ -23,6 +23,7 @@ public class ResponseCachingContext
         private CacheControlHeaderValue _requestCacheControl;
         private CacheControlHeaderValue _responseCacheControl;
         private DateTimeOffset _responseTime;
+        private static readonly CacheControlHeaderValue EmptyCacheControl = new CacheControlHeaderValue();
 
         public ResponseCachingContext(HttpContext httpContext, IResponseCache cache)
         {
@@ -78,7 +79,7 @@ private CacheControlHeaderValue RequestCacheControl
             {
                 if (_requestCacheControl == null)
                 {
-                    _requestCacheControl = RequestHeaders.CacheControl ?? new CacheControlHeaderValue();
+                    _requestCacheControl = RequestHeaders.CacheControl ?? EmptyCacheControl;
                 }
                 return _requestCacheControl;
             }
@@ -90,7 +91,7 @@ private CacheControlHeaderValue ResponseCacheControl
             {
                 if (_responseCacheControl == null)
                 {
-                    _responseCacheControl = ResponseHeaders.CacheControl ?? new CacheControlHeaderValue();
+                    _responseCacheControl = ResponseHeaders.CacheControl ?? EmptyCacheControl;
                 }
                 return _responseCacheControl;
             }
@@ -249,7 +250,7 @@ private bool ValidateEncoding(ResponseHeaders cachedResponsHeaders)
 
         private bool EntryIsFresh(ResponseHeaders responseHeaders, TimeSpan age, bool verifyAgainstRequest)
         {
-            var responseCacheControl = responseHeaders.CacheControl ?? new CacheControlHeaderValue();
+            var responseCacheControl = responseHeaders.CacheControl ?? EmptyCacheControl;
 
             // Add min-fresh requirements
             if (verifyAgainstRequest)
@@ -329,7 +330,6 @@ internal async Task<bool> TryServeFromCacheAsync()
 
                         if (_responseType == ResponseType.HeadersOnly)
                         {
-                            response.ContentLength = 0;
                             responseServed = true;
                         }
                         else if (_responseType == ResponseType.FullReponse)