@Override
        public void startDocument() throws SAXException {
            LOGGER.debug("startDocument()");
            super.startDocument();
            saxDocumentSerializer.reset();
            saxDocumentSerializer.startDocument();
        }
A proof of concept for https://github.com/gchq/stroom/issues/1945
Trying to prove that we can generate a fast infoset vocab
for some xml and then append to it. This is to reduce the volume of data
stored in the LMDB ref data store.
stroom-pipeline/src/test/java/stroom/pipeline/refdata/TestFastInfosetVocab.java