@Override
    public void endPrefixMapping(final String prefix) throws SAXException {
        if (buffer) {
            events.add(new EndPrefixMapping(prefix));
        } else {
            super.endPrefixMapping(prefix);
        }
    }
Buffers a endPrefixMapping event if buffer is set to true.

@param prefix the prefix that was being mapped. This is the empty string
              when a default mapping scope ends.
@throws SAXException Not thrown.
@see stroom.pipeline.filter.AbstractXMLFilter#endPrefixMapping(java.lang.String)
stroom-pipeline/src/test/java/stroom/pipeline/util/BufferFilter.java