@Override
    protected <T> void writeTo(OutputStream out, T message, Schema<T> schema)
            throws IOException
    {
        ProtobufIOUtil.writeTo(out, message, schema, buf());
    }
Test runtime collection fields with {@link CollectionSchema} via protobuf ser/deser.

@author David Yu
@created Jan 26, 2011
protostuff-runtime/src/test/java/io/protostuff/runtime/ProtobufRuntimeCollectionSchemaTest.java