1 files changed, 6 insertions, 0 deletions
diff --git a/csharp/ProtocolBuffers/UnknownFieldSet.cs b/csharp/ProtocolBuffers/UnknownFieldSet.cs
index b9bbfe3a..787126ad 100644
--- a/csharp/ProtocolBuffers/UnknownFieldSet.cs
+++ b/csharp/ProtocolBuffers/UnknownFieldSet.cs
@@ -17,6 +17,8 @@ using System;
 
 namespace Google.ProtocolBuffers {
   public class UnknownFieldSet {
+    public int SerializedSizeAsMessageSet;
+
     public void WriteTo(CodedOutputStream output) {
       throw new NotImplementedException();
     }
@@ -29,5 +31,9 @@ namespace Google.ProtocolBuffers {
         throw new NotImplementedException();
       }
     }
+
+    internal void WriteAsMessageSetTo(CodedOutputStream output) {
+      throw new NotImplementedException();
+    }
   }
 }