A few performance tweaks of the ICodedOutputStream interface/implementation
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
index 60a8b8d..4ba2149 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
@@ -119,7 +119,7 @@
     

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

       int size = SerializedSize;

-      if (HasOptionalMessage) {

+      if (hasOptionalMessage) {

         output.WriteMessage(1, "optional_message", OptionalMessage);

       }

       if (repeatedMessage_.Count > 0) {

@@ -135,7 +135,7 @@
         if (size != -1) return size;

         

         size = 0;

-        if (HasOptionalMessage) {

+        if (hasOptionalMessage) {

           size += pb::CodedOutputStream.ComputeMessageSize(1, OptionalMessage);

         }

         foreach (global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize element in RepeatedMessageList) {

@@ -275,7 +275,7 @@
             }

             case 10: {

               global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize.Builder subBuilder = global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize.CreateBuilder();

-              if (HasOptionalMessage) {

+              if (result.hasOptionalMessage) {

                 subBuilder.MergeFrom(OptionalMessage);

               }

               input.ReadMessage(subBuilder, extensionRegistry);

@@ -297,7 +297,7 @@
       

       

       public bool HasOptionalMessage {

-       get { return result.HasOptionalMessage; }

+       get { return result.hasOptionalMessage; }

       }

       public global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize OptionalMessage {

         get { return result.OptionalMessage; }

@@ -317,7 +317,7 @@
       }

       public Builder MergeOptionalMessage(global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize value) {

         pb::ThrowHelper.ThrowIfNull(value, "value");

-        if (result.HasOptionalMessage &&

+        if (result.hasOptionalMessage &&

             result.optionalMessage_ != global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize.DefaultInstance) {

             result.optionalMessage_ = global::Google.ProtocolBuffers.TestProtos.TestOptimizedForSize.CreateBuilder(result.optionalMessage_).MergeFrom(value).BuildPartial();

         } else {