@Override
    public void characters(final char[] ch, final int start, final int length) throws SAXException {
        handler.characters(ch, start, length);
        super.characters(ch, start, length);
    }
@param ch     the characters from the XML document
@param start  the start position in the array
@param length the number of characters to read from the array
@throws SAXException any SAX exception, possibly wrapping another exception
@see #ignorableWhitespace
@see Locator
@see AbstractXMLFilter#characters(char[],
int, int)
stroom-pipeline/src/main/java/stroom/pipeline/writer/XMLWriter.java