@Override
    public void startDocument() throws SAXException {
        depth = 0;
        alreadyWarnedAboutForeign = false;
        alreadyWarnedAboutFiltering = false;
        rootSeen = false;
        contentHandler.startDocument();
    }
@see org.xml.sax.helpers.XMLFilterImpl#startDocument()
src/nu/validator/xml/NamespaceDroppingXMLReaderWrapper.java