code: protected void count_and_yield(boolean moreExpected) throws SAXException
    {
      if(!moreExpected) eventcounter=0;
      
      if(--eventcounter<=0)
        {
          co_yield(true);
          eventcounter=frequency;
        }
    }
docs: <p>In the SAX delegation code, I've inlined the count-down in
  the hope of encouraging compilers to deliver better
  performance. However, if we subclass (eg to directly connect the
  output to a DTM builder), that would require calling super in
  order to run that logic... which seems inelegant.  Hence this
  routine for the convenience of subclasses: every [frequency]
  invocations, issue a co_yield.</p>
  
  @param moreExepected Should always be true unless this is being called
  at the end of endDocument() handling.