code: public XMLEvent processEvent() throws XMLStreamException, SNAXUserException {
          checkState(xmlReader != null, "startParsing() was never called");
          checkState(isIncremental, "startParsing() was never called");
          return processEvent(xmlReader.nextEvent());
      }
docs: Consumes the next XML event.  This method may only be
  called following a call to <code>startParsing()</code>.
  @return the XMLEvent that was processed
  @throws XMLStreamException if there is an error with the underlying XML
  @throws SNAXUserException if there is an error in an attached <code>ElementHandler</code>
  @throws NoSuchElementException if no XML remains to be processed