private void fastInfosetEndPrefixMapping(final String prefix) throws SAXException {
        LOGGER.trace("saxDocumentSerializer - endPrefixMapping({}})", prefix);
        saxDocumentSerializer.endPrefixMapping(prefix);
        appliedPrefixToUriMap.remove(prefix);
//        appliedPrefixToUriMap.values()
//                .removeIf(value ->
//                        ((value == null && prefix == null)
//                                || (value != null && value.equals(prefix))));
    }
@param ch     An array of characters.
@param start  The starting position in the array.
@param length The number of characters to use from the array.
@throws org.xml.sax.SAXException The client may throw an exception during processing.
@see stroom.pipeline.filter.AbstractXMLFilter#characters(char[],
int, int)
stroom-pipeline/src/main/java/stroom/pipeline/refdata/ReferenceDataFilter.java