Imported Upstream version 5.10.0.47

Former-commit-id: d0813289fa2d35e1f8ed77530acb4fb1df441bc0

external/binary-reference-assemblies/src/v4.7.1/System.ServiceModel.Routing.extra.cs

@@ -0,0 +1,8 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.ServiceModel.Routing
+{
+    interface IDuplexRouterCallback {}
+}