Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/rx/Rx/NET/Source/System.Reactive.Interfaces/IObservable.cs

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if NO_RXINTERFACES
+namespace System
+{
+    /// <summary>
+    /// Represents a push-style collection.
+    /// </summary>
+#if !NO_VARIANCE
+    public interface IObservable<out T>
+#else
+    public interface IObservable<T>
+#endif
+    {
+        /// <summary>
+        /// Subscribes an observer to the observable sequence.
+        /// </summary>
+        IDisposable Subscribe(IObserver<T> observer);
+    }
+}
+#elif !WINDOWSPHONE7 // TypeForwardedTo is not presen on windows phone 7 so we can't really target
+[assembly: System.Runtime.CompilerServices.TypeForwardedTo(typeof(System.IObservable<>))]
+#endif
+