Reverting SignalR.Core/Infrastructure/CancellationTokenExtensions.cs to old version

http://pastie.org/pastes/9895879/text?key=ifs697ru97thfxedyj91oq

src/Microsoft.AspNet.SignalR.Core/Infrastructure/CancellationTokenExtensions.cs

@@ -10,16 +10,14 @@ namespace Microsoft.AspNet.SignalR.Infrastructure
 {
     internal static class CancellationTokenExtensions
     {
-        private delegate CancellationTokenRegistration RegisterDelegate(ref CancellationToken token, Action<object> callback, object state);
-
-        private static readonly RegisterDelegate _tokenRegister = ResolveRegisterDelegate();
-
         public static IDisposable SafeRegister(this CancellationToken cancellationToken, Action<object> callback, object state)
         {
             var callbackWrapper = new CancellationCallbackWrapper(callback, state);
 
             // Ensure delegate continues to use the C# Compiler static delegate caching optimization.
-            CancellationTokenRegistration registration = _tokenRegister(ref cancellationToken, InvokeCallback, callbackWrapper);
+            CancellationTokenRegistration registration = cancellationToken.Register(s => Cancel(s),
+                                                                                    callbackWrapper,
+                                                                                    useSynchronizationContext: false);
 
             var disposeCancellationState = new DiposeCancellationState(callbackWrapper, registration);
 
@@ -27,7 +25,7 @@ namespace Microsoft.AspNet.SignalR.Infrastructure
             return new DisposableAction(s => Dispose(s), disposeCancellationState);
         }
 
-        private static void InvokeCallback(object state)
+        private static void Cancel(object state)
         {
             ((CancellationCallbackWrapper)state).TryInvoke();
         }
@@ -37,56 +35,6 @@ namespace Microsoft.AspNet.SignalR.Infrastructure
             ((DiposeCancellationState)state).TryDispose();
         }
 
-        [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes", Justification = "This method should never throw since it runs as part of field initialzation")]
-        private static RegisterDelegate ResolveRegisterDelegate()
-        {
-            // The fallback is just a normal register that capatures the execution context.
-            RegisterDelegate fallback = (ref CancellationToken token, Action<object> callback, object state) =>
-            {
-                return token.Register(callback, state);
-            };
-
-#if NETFX_CORE || PORTABLE
-            return fallback;
-#else
-
-            MethodInfo methodInfo = null;
-
-            try
-            {
-                // By default we don't want to capture the execution context,
-                // since this is internal we need to create a delegate to this up front
-                methodInfo = typeof(CancellationToken).GetMethod("InternalRegisterWithoutEC",
-                                                                 BindingFlags.NonPublic | BindingFlags.Instance,
-                                                                 binder: null,
-                                                                 types: new[] { typeof(Action<object>), typeof(object) },
-                                                                 modifiers: null);
-            }
-            catch
-            {
-                // Swallow this exception. Being extra paranoid, we don't want anything to break in case this dirty
-                // reflection hack fails for any reason
-            }
-
-            // If the method was removed then fallback to the regular method
-            if (methodInfo == null)
-            {
-                return fallback;
-            }
-
-            try
-            {
-
-                return (RegisterDelegate)Delegate.CreateDelegate(typeof(RegisterDelegate), null, methodInfo);
-            }
-            catch
-            {
-                // If this fails for whatever reason just fallback to normal register
-                return fallback;
-            }
-#endif
-        }
-
         private class DiposeCancellationState
         {
             private readonly CancellationCallbackWrapper _callbackWrapper;