diff --git a/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.FeatureCollection.cs b/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.FeatureCollection.cs
index 0fa8447d8f..293c3facc4 100644
--- a/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.FeatureCollection.cs
+++ b/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.FeatureCollection.cs
@@ -7,6 +7,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Http.Features;
 using Microsoft.Extensions.Primitives;
 
@@ -145,7 +146,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             }
         }
 
-        IDictionary<string, StringValues> IHttpRequestFeature.Headers
+        IHeaderDictionary IHttpRequestFeature.Headers
         {
             get
             {
@@ -197,7 +198,7 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
             }
         }
 
-        IDictionary<string, StringValues> IHttpResponseFeature.Headers
+        IHeaderDictionary IHttpResponseFeature.Headers
         {
             get
             {
diff --git a/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs b/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs
index 945bd3a105..f772b32da8 100644
--- a/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs
+++ b/src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs
@@ -2,14 +2,13 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNet.Http.Features;
+using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Server.Kestrel.Infrastructure;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
@@ -55,13 +54,13 @@ namespace Microsoft.AspNet.Server.Kestrel.Http
         public string Path { get; set; }
         public string QueryString { get; set; }
         public string HttpVersion { get; set; }
-        public IDictionary<string, StringValues> RequestHeaders { get; set; }
+        public IHeaderDictionary RequestHeaders { get; set; }
         public MessageBody MessageBody { get; set; }
         public Stream RequestBody { get; set; }
 
         public int StatusCode { get; set; }
         public string ReasonPhrase { get; set; }
-        public IDictionary<string, StringValues> ResponseHeaders { get; set; }
+        public IHeaderDictionary ResponseHeaders { get; set; }
         public Stream ResponseBody { get; set; }
 
         public Stream DuplexStream { get; set; }
diff --git a/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.cs b/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.cs
index 18b19c114e..beb926447c 100644
--- a/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.cs
+++ b/src/Microsoft.AspNet.Server.Kestrel/Http/FrameHeaders.cs
@@ -5,16 +5,31 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
+using Microsoft.AspNet.Http;
 using Microsoft.Extensions.Primitives;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http
 {
-    public abstract class FrameHeaders : IDictionary<string, StringValues>
+    public abstract class FrameHeaders : IHeaderDictionary
     {
         protected Dictionary<string, StringValues> MaybeUnknown;
 
         protected Dictionary<string, StringValues> Unknown => MaybeUnknown ?? (MaybeUnknown = new Dictionary<string, StringValues>(StringComparer.OrdinalIgnoreCase));
 
+        StringValues IHeaderDictionary.this[string key]
+        {
+            get
+            {
+                StringValues value;
+                TryGetValueFast(key, out value);
+                return value;
+            }
+            set
+            {
+                SetValueFast(key, value);
+            }
+        }
+
         StringValues IDictionary<string, StringValues>.this[string key]
         {
             get