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diff --git a/csharp/src/ProtocolBuffers/RpcUtil.cs b/csharp/src/ProtocolBuffers/RpcUtil.cs
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+#region Copyright notice and license
+
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// http://github.com/jskeet/dotnet-protobufs/
+// Original C++/Java/Python code:
+// http://code.google.com/p/protobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Google.ProtocolBuffers
+{
+    /// <summary>
+    /// Grab-bag of utility functions useful when dealing with RPCs.
+    /// </summary>
+    public static class RpcUtil
+    {
+        /// <summary>
+        /// Converts an Action[IMessage] to an Action[T].
+        /// </summary>
+        public static Action<T> SpecializeCallback<T>(Action<IMessage> action)
+            where T : IMessage<T>
+        {
+            return message => action(message);
+        }
+
+        /// <summary>
+        /// Converts an Action[T] to an Action[IMessage].
+        /// The generalized action will accept any message object which has
+        /// the same descriptor, and will convert it to the correct class
+        /// before calling the original action. However, if the generalized
+        /// callback is given a message with a different descriptor, an
+        /// exception will be thrown.
+        /// </summary>
+        public static Action<IMessage> GeneralizeCallback<TMessage, TBuilder>(Action<TMessage> action,
+                                                                              TMessage defaultInstance)
+            where TMessage : class, IMessage<TMessage, TBuilder>
+            where TBuilder : IBuilder<TMessage, TBuilder>
+        {
+            return message =>
+                       {
+                           TMessage castMessage = message as TMessage;
+                           if (castMessage == null)
+                           {
+                               castMessage = defaultInstance.CreateBuilderForType().MergeFrom(message).Build();
+                           }
+                           action(castMessage);
+                       };
+        }
+    }
+}
+\ No newline at end of file