Include IHttpClientCertificateFeature changes.

src/Microsoft.AspNet.Server.WebListener/FeatureContext.cs

@@ -308,11 +308,11 @@ namespace Microsoft.AspNet.Server.WebListener
             set { _clientCert = value; }
         }
 
-        async Task<X509Certificate> IHttpClientCertificateFeature.GetClientCertificateAsync()
+        async Task<X509Certificate> IHttpClientCertificateFeature.GetClientCertificateAsync(CancellationToken cancellationToken)
         {
             if (_clientCert == null)
             {
-                _clientCert = await Request.GetClientCertificateAsync();
+                _clientCert = await Request.GetClientCertificateAsync(cancellationToken);
             }
             return _clientCert;
         }

src/Microsoft.Net.Server/RequestProcessing/ClientCertLoader.cs

@@ -162,8 +162,9 @@ namespace Microsoft.Net.Server
         // ERROR_NOT_FOUND - which means the client did not provide the cert
         // If this is important, the server should respond with 403 forbidden
         // HTTP.SYS will not do this for you automatically
-        internal Task LoadClientCertificateAsync()
+        internal Task LoadClientCertificateAsync(CancellationToken cancellationToken)
         {
+            // TODO: cancellation support? Abort the request?
             uint size = CertBoblSize;
             bool retry;
             do

src/Microsoft.Net.Server/RequestProcessing/Request.cs

@@ -455,7 +455,7 @@ namespace Microsoft.Net.Server
         // Populates the client certificate.  The result may be null if there is no client cert.
         // TODO: Does it make sense for this to be invoked multiple times (e.g. renegotiate)? Client and server code appear to
         // enable this, but it's unclear what Http.Sys would do.
-        public async Task<X509Certificate> GetClientCertificateAsync()
+        public async Task<X509Certificate> GetClientCertificateAsync(CancellationToken cancellationToken = default(CancellationToken))
         {
             if (SslStatus == SslStatus.Insecure)
             {
@@ -471,7 +471,7 @@ namespace Microsoft.Net.Server
             ClientCertLoader certLoader = new ClientCertLoader(RequestContext);
             try
             {
-                await certLoader.LoadClientCertificateAsync().SupressContext();
+                await certLoader.LoadClientCertificateAsync(cancellationToken).SupressContext();
                 // Populate the environment.
                 if (certLoader.ClientCert != null)
                 {