Some feedback

Author: JunTaoLuo

src/Microsoft.AspNetCore.ResponseCaching/Internal/DefaultResponseCacheEntrySerializer.cs

@@ -71,7 +71,7 @@ public static object Read(BinaryReader reader)
         }
 
         // Serialization Format
-        // Creation time (DateTimeOffset, RoundTripFormat, InvariantCulture)
+        // Creation time - UtcTicks (long)
         // Status code (int)
         // Header count (int)
         // Header(s)
@@ -81,7 +81,7 @@ public static object Read(BinaryReader reader)
         // Body (byte[])
         private static CachedResponse ReadCachedResponse(BinaryReader reader)
         {
-            var created = DateTimeOffset.ParseExact(reader.ReadString(), RoundTripFormat, CultureInfo.InvariantCulture);
+            var created = new DateTimeOffset(reader.ReadInt64(), TimeSpan.Zero);
             var statusCode = reader.ReadInt32();
             var headerCount = reader.ReadInt32();
             var headers = new HeaderDictionary();
@@ -139,7 +139,7 @@ public static void Write(BinaryWriter writer, object entry)
         private static void WriteCachedResponse(BinaryWriter writer, CachedResponse entry)
         {
             writer.Write(nameof(CachedResponse));
-            writer.Write(entry.Created.ToString(RoundTripFormat, CultureInfo.InvariantCulture));
+            writer.Write(entry.Created.UtcTicks);
             writer.Write(entry.StatusCode);
             writer.Write(entry.Headers.Count);
             foreach (var header in entry.Headers)

src/Microsoft.AspNetCore.ResponseCaching/Internal/Helpers.cs

@@ -374,7 +374,7 @@ internal async Task<bool> TryServeFromCacheAsync()
 
                         if (body.Length > 0)
                         {
-                            await response.Body.WriteAsync(body, 0, body.Length).SupressContext();
+                            await response.Body.WriteAsync(body, 0, body.Length);
                         }
 
                         responseServed = true;

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingContext.cs

@@ -2,10 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.IO;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.ResponseCaching.Internal;
 
 namespace Microsoft.AspNetCore.ResponseCaching
 {
@@ -14,6 +12,11 @@ public class ResponseCachingMiddleware
     {
         private readonly RequestDelegate _next;
         private readonly IResponseCache _cache;
+        private static readonly Func<object, Task> OnStartingCallback = state =>
+        {
+            ((ResponseCachingContext)state).OnResponseStarting();
+            return Task.FromResult(0);
+        };
 
         public ResponseCachingMiddleware(RequestDelegate next, IResponseCache cache)
         {
@@ -50,11 +53,7 @@ public async Task Invoke(HttpContext context)
                     cachingContext.HookResponseStream();
 
                     // Subscribe to OnStarting event
-                    context.Response.OnStarting(state =>
-                    {
-                        (state as ResponseCachingContext).OnResponseStarting();
-                        return Helpers.CompletedTask;
-                    }, cachingContext);
+                    context.Response.OnStarting(OnStartingCallback, cachingContext);
 
                     await _next(context);
 

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingMiddleware.cs

@@ -494,7 +494,7 @@ private class TestHttpSendFileFeature : IHttpSendFileFeature
         {
             public Task SendFileAsync(string path, long offset, long? count, CancellationToken cancellation)
             {
-                return Helpers.CompletedTask;
+                return Task.FromResult(0);
             }
         }
     }