code: public void startParsing(Reader reader, T data) throws XMLStreamException {
          checkState(model != null, "No model was set");
          init(reader, data);
          isIncremental = true;
      }
docs: Begin incremental parsing of a data stream, represented by a Reader.  This will initialize
  the parser but will not perform any parsing.  Callers should then use hasMoreEvents() and
  processEvent() to consume XML events until the document has been completely parsed.
  
  @param reader XML content to process
  @param data optional, user-defined object to be passed as an argument to ElementHandlers
  @throws XMLStreamException if an error occurs during initialization