Remove usage of TaskCache

src/Microsoft.AspNetCore.Localization.Routing/Microsoft.AspNetCore.Localization.Routing.csproj

@@ -17,7 +17,6 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Routing.Abstractions" Version="$(AspNetCoreVersion)" />
-    <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All"/>
   </ItemGroup>
 
 </Project>

src/Microsoft.AspNetCore.Localization.Routing/RouteDataRequestCultureProvider.cs

@@ -51,7 +51,7 @@ namespace Microsoft.AspNetCore.Localization.Routing
             if (culture == null && uiCulture == null)
             {
                 // No values specified for either so no match
-                return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+                return NullProviderCultureResult;
             }
 
             if (culture != null && uiCulture == null)

src/Microsoft.AspNetCore.Localization/AcceptLanguageHeaderRequestCultureProvider.cs

@@ -34,7 +34,7 @@ namespace Microsoft.AspNetCore.Localization
 
             if (acceptLanguageHeader == null || acceptLanguageHeader.Count == 0)
             {
-                return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+                return NullProviderCultureResult;
             }
 
             var languages = acceptLanguageHeader.AsEnumerable();
@@ -49,12 +49,12 @@ namespace Microsoft.AspNetCore.Localization
             var orderedLanguages = languages.OrderByDescending(h => h, StringWithQualityHeaderValueComparer.QualityComparer)
                 .Select(x => x.Value).ToList();
 
-            if (orderedLanguages.Any())
+            if (orderedLanguages.Count > 0)
             {
                 return Task.FromResult(new ProviderCultureResult(orderedLanguages));
             }
 
-            return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+            return NullProviderCultureResult;
         }
     }
 }

src/Microsoft.AspNetCore.Localization/CookieRequestCultureProvider.cs

@@ -40,7 +40,7 @@ namespace Microsoft.AspNetCore.Localization
 
             if (string.IsNullOrEmpty(cookie))
             {
-                return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+                return NullProviderCultureResult;
             }
 
             var providerResultCulture = ParseCookieValue(cookie);

src/Microsoft.AspNetCore.Localization/Microsoft.AspNetCore.Localization.csproj

@@ -18,7 +18,6 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.Http.Extensions" Version="$(AspNetCoreVersion)" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="$(AspNetCoreVersion)" />
-    <PackageReference Include="Microsoft.Extensions.TaskCache.Sources" Version="$(AspNetCoreVersion)" PrivateAssets="All"/>
   </ItemGroup>
 
 </Project>

src/Microsoft.AspNetCore.Localization/QueryStringRequestCultureProvider.cs

@@ -37,7 +37,7 @@ namespace Microsoft.AspNetCore.Localization
             var request = httpContext.Request;
             if (!request.QueryString.HasValue)
             {
-                return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+                return NullProviderCultureResult;
             }
 
             string queryCulture = null;
@@ -56,7 +56,7 @@ namespace Microsoft.AspNetCore.Localization
             if (queryCulture == null && queryUICulture == null)
             {
                 // No values specified for either so no match
-                return TaskCache<ProviderCultureResult>.DefaultCompletedTask;
+                return NullProviderCultureResult;
             }
 
             if (queryCulture != null && queryUICulture == null)

src/Microsoft.AspNetCore.Localization/RequestCultureProvider.cs

@@ -12,6 +12,12 @@ namespace Microsoft.AspNetCore.Localization
     /// </summary>
     public abstract class RequestCultureProvider : IRequestCultureProvider
     {
+        /// <summary>
+        /// Result that indicates that this instance of <see cref="RequestCultureProvider" /> could not determine the
+        /// request culture.
+        /// </summary>
+        protected static readonly Task<ProviderCultureResult> NullProviderCultureResult = Task.FromResult(default(ProviderCultureResult));
+
         /// <summary>
         /// The current options for the <see cref="RequestLocalizationMiddleware"/>.
         /// </summary>