Fully converted over to ICodedOutputStream for all WriteTo derivations
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
index 9a29d41..2002d8d 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
@@ -70,7 +70,7 @@
       }

     }

     

-    public override void WriteTo(pb::CodedOutputStream output) {

+    public override void WriteTo(pb::ICodedOutputStream output) {

       int size = SerializedSize;

       if (HasD) {

         output.WriteInt32(1, "d", D);