@Override
    protected <T> byte[] toByteArray(T message, Schema<T> schema)
    {
        return XmlXIOUtil.toByteArray(message, schema, buf());
    }
Test runtime collection fields with {@link CollectionSchema} via xml ser/deser.

@author David Yu
@created Jan 27, 2011
protostuff-xml/src/test/java/io/protostuff/XmlXRuntimeCollectionSchemaTest.java