Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/rx/Rx/NET/Source/System.Reactive.Interfaces/Reactive/Disposables/ICancelable.cs

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+namespace System.Reactive.Disposables
+{
+    /// <summary>
+    /// Disposable resource with dipsosal state tracking.
+    /// </summary>
+    public interface ICancelable : IDisposable
+    {
+        /// <summary>
+        /// Gets a value that indicates whether the object is disposed.
+        /// </summary>
+        bool IsDisposed { get; }
+    }
+}