Fix for public constructor on messages
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
index 8ba6ecd..149f218 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
@@ -64,6 +64,7 @@
   [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]

   [global::System.CodeDom.Compiler.GeneratedCodeAttribute("ProtoGen", "2.3.0.277")]

   public sealed partial class TestEmbedOptimizedForSize : pb::GeneratedMessage<TestEmbedOptimizedForSize, TestEmbedOptimizedForSize.Builder> {

+    private TestEmbedOptimizedForSize() { }

     private static readonly TestEmbedOptimizedForSize defaultInstance = new Builder().BuildPartial();

     private static readonly string[] _testEmbedOptimizedForSizeFieldNames = new string[] { "optional_message", "repeated_message" };

     private static readonly uint[] _testEmbedOptimizedForSizeFieldTags = new uint[] { 10, 18 };