@Override
    public void processingInstruction(final String target, final String data) throws SAXException {
        handler.processingInstruction(target, data);
    }
Receive notification of a processing instruction.
<p>
<p>
The Parser will invoke this method once for each processing instruction
found: note that processing instructions may occur before or after the
main document element.
</p>
<p>
<p>
A SAX parser must never report an XML declaration (XML 1.0, section 2.8)
or a text declaration (XML 1.0, section 4.3.1) using this method.
</p>
<p>
<p>
Like {@link #characters characters()}, processing instruction data may
have characters that need more than one <code>char</code> value.
</p>

@param target the processing instruction target
@param data   the processing instruction data, or null if none was supplied.
              The data does not include any whitespace separating it from
              the target
@throws org.xml.sax.SAXException any SAX exception, possibly wrapping another exception
stroom-pipeline/src/main/java/stroom/pipeline/filter/ContentHandlerAdaptor.java