Remove RequestCulture caching as perf testing shows it has no benefit

src/Microsoft.AspNet.Localization/AcceptLanguageHeaderRequestCultureStrategy.cs

@@ -15,7 +15,7 @@ namespace Microsoft.AspNet.Localization
     public class AcceptLanguageHeaderRequestCultureStrategy : RequestCultureStrategy
     {
         /// <summary>
-        /// The maximum number of values in the Accept-Language header to attempt to create a <see cref="CultureInfo"/>
+        /// The maximum number of values in the Accept-Language header to attempt to create a <see cref="System.Globalization.CultureInfo"/>
         /// from for the current request.
         /// Defaults to <c>3</c>.
         /// </summary>
@@ -52,7 +52,7 @@ namespace Microsoft.AspNet.Localization
                     var culture = CultureInfoCache.GetCultureInfo(language.Value);
                     if (culture != null)
                     {
-                        var requestCulture = RequestCulture.GetRequestCulture(culture);
+                        var requestCulture = new RequestCulture(culture);
 
                         requestCulture = ValidateRequestCulture(requestCulture);
 

src/Microsoft.AspNet.Localization/CookieRequestCultureStrategy.cs

@@ -98,7 +98,7 @@ namespace Microsoft.AspNet.Localization
                 return null;
             }
 
-            return RequestCulture.GetRequestCulture(culture, uiCulture);
+            return new RequestCulture(culture, uiCulture);
         }
     }
 }

src/Microsoft.AspNet.Localization/QueryStringRequestCultureStrategy.cs

@@ -67,7 +67,7 @@ namespace Microsoft.AspNet.Localization
                 return null;
             }
 
-            var requestCulture = RequestCulture.GetRequestCulture(culture, uiCulture);
+            var requestCulture = new RequestCulture(culture, uiCulture);
 
             requestCulture = ValidateRequestCulture(requestCulture);
 

src/Microsoft.AspNet.Localization/RequestCulture.cs

@@ -1,7 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved. 
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. 
 
-using System.Collections.Concurrent;
 using System.Globalization;
 using Microsoft.Framework.Internal;
 
@@ -12,15 +11,24 @@ namespace Microsoft.AspNet.Localization
     /// </summary>
     public class RequestCulture
     {
-        private static readonly ConcurrentDictionary<CacheKey, RequestCulture> _cache = new ConcurrentDictionary<CacheKey, RequestCulture>();
+        /// <summary>
-
+        /// Creates a new <see cref="RequestCulture"/> object has its <see cref="Culture"/> and <see cref="UICulture"/>
-        private RequestCulture([NotNull] CultureInfo culture)
+        /// properties set to the same <see cref="CultureInfo"/> value.
+        /// </summary>
+        /// <param name="culture">The <see cref="CultureInfo"/> for the request.</param>
+        public RequestCulture([NotNull] CultureInfo culture)
             : this (culture, culture)
         {
 
         }
 
-        private RequestCulture([NotNull] CultureInfo culture, [NotNull] CultureInfo uiCulture)
+        /// <summary>
+        /// Creates a new <see cref="RequestCulture"/> object has its <see cref="Culture"/> and <see cref="UICulture"/>
+        /// properties set to the respective <see cref="CultureInfo"/> values provided.
+        /// </summary>
+        /// <param name="culture">The <see cref="CultureInfo"/> for the request to be used for formatting.</param>
+        /// <param name="uiCulture">The <see cref="CultureInfo"/> for the request to be used for text, i.e. language.</param>
+        public RequestCulture([NotNull] CultureInfo culture, [NotNull] CultureInfo uiCulture)
         {
             Culture = culture;
             UICulture = uiCulture;
@@ -35,66 +43,5 @@ namespace Microsoft.AspNet.Localization
         /// Gets the <see cref="CultureInfo"/> for the request to be used for text, i.e. language;
         /// </summary>
         public CultureInfo UICulture { get; }
-
-        /// <summary>
-        /// Gets a cached <see cref="RequestCulture"/> instance that has its <see cref="Culture"/> and <see cref="UICulture"/>
-        /// properties set to the same <see cref="CultureInfo"/> value.
-        /// </summary>
-        /// <param name="culture">The <see cref="CultureInfo"/> for the request.</param>
-        public static RequestCulture GetRequestCulture([NotNull] CultureInfo culture)
-        {
-            return GetRequestCulture(culture, culture);
-        }
-
-        /// <summary>
-        /// Gets a cached <see cref="RequestCulture"/> instance that has its <see cref="Culture"/> and <see cref="UICulture"/>
-        /// properties set to the respective <see cref="CultureInfo"/> values provided.
-        /// </summary>
-        /// <param name="culture">The <see cref="CultureInfo"/> for the request to be used for formatting.</param>
-        /// <param name="uiCulture">The <see cref="CultureInfo"/> for the request to be used for text, i.e. language.</param>
-        /// <returns></returns>
-        public static RequestCulture GetRequestCulture([NotNull] CultureInfo culture, [NotNull] CultureInfo uiCulture)
-        {
-            var key = new CacheKey(culture, uiCulture);
-            return _cache.GetOrAdd(key, k => new RequestCulture(culture, uiCulture));
-        }
-
-        private class CacheKey
-        {
-            private readonly int _hashCode;
-
-            public CacheKey(CultureInfo culture, CultureInfo uiCulture)
-            {
-                Culture = culture;
-                UICulture = uiCulture;
-                _hashCode = new { Culture, UICulture }.GetHashCode();
-            }
-
-            public CultureInfo Culture { get; }
-
-            public CultureInfo UICulture { get; }
-
-            public bool Equals(CacheKey other)
-            {
-                return Culture == other.Culture && UICulture == other.UICulture;
-            }
-
-            public override bool Equals(object obj)
-            {
-                var other = obj as CacheKey;
-
-                if (other != null)
-                {
-                    return Equals(other);
-                }
-
-                return base.Equals(obj);
-            }
-
-            public override int GetHashCode()
-            {
-                return _hashCode;
-            }
-        }
     }
 }

src/Microsoft.AspNet.Localization/RequestCultureStrategy.cs

@@ -41,12 +41,12 @@ namespace Microsoft.AspNet.Localization
 
             if (Options.SupportedCultures != null && !Options.SupportedCultures.Contains(result.Culture))
             {
-                result = RequestCulture.GetRequestCulture(Options.DefaultRequestCulture.Culture, result.UICulture);
+                result = new RequestCulture(Options.DefaultRequestCulture.Culture, result.UICulture);
             }
 
             if (Options.SupportedUICultures != null && !Options.SupportedUICultures.Contains(result.UICulture))
             {
-                result = RequestCulture.GetRequestCulture(result.Culture, Options.DefaultRequestCulture.UICulture);
+                result = new RequestCulture(result.Culture, Options.DefaultRequestCulture.UICulture);
             }
 
             if (requestCulture.Culture != result.Culture && requestCulture.UICulture != result.UICulture)

src/Microsoft.AspNet.Localization/RequestLocalizationMiddleware.cs

@@ -38,7 +38,7 @@ namespace Microsoft.AspNet.Localization
         public async Task Invoke([NotNull] HttpContext context)
         {
             var requestCulture = _options.DefaultRequestCulture ??
-                RequestCulture.GetRequestCulture(CultureInfo.CurrentCulture, CultureInfo.CurrentUICulture);
+                new RequestCulture(CultureInfo.CurrentCulture, CultureInfo.CurrentUICulture);
 
             IRequestCultureStrategy winningStrategy = null;
 

src/Microsoft.AspNet.Localization/RequestLocalizationOptions.cs

@@ -17,7 +17,7 @@ namespace Microsoft.AspNet.Localization
         /// </summary>
         public RequestLocalizationOptions()
         {
-            DefaultRequestCulture = RequestCulture.GetRequestCulture(CultureInfo.CurrentCulture, CultureInfo.CurrentUICulture);
+            DefaultRequestCulture = new RequestCulture(CultureInfo.CurrentCulture, CultureInfo.CurrentUICulture);
 
             RequestCultureStrategies = new List<IRequestCultureStrategy>
             {