imported signalr 1.1.3 into NzbDrone.

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

@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.md in the project root for license information.
+
+using System.Diagnostics;
+
+namespace Microsoft.AspNet.SignalR.Infrastructure
+{
+    public interface IPerformanceCounter
+    {
+        string CounterName { get; }
+        long Decrement();
+        long Increment();
+        long IncrementBy(long value);
+        CounterSample NextSample();
+        long RawValue { get; set; }
+        void Close();
+        void RemoveInstance();
+    }
+}