code: private void co_entry_pause() throws SAXException
    {
      if(fCoroutineManager==null)
      {
        // Nobody called init()? Do it now...
        init(null,-1,-1);
      }
  
      try
      {
        Object arg=fCoroutineManager.co_entry_pause(fSourceCoroutineID);
        if(arg==Boolean.FALSE)
          co_yield(false);
      }
      catch(NoSuchMethodException e)
      {
        // Coroutine system says we haven't registered. That's an
        // application coding error, and is unrecoverable.
        if(DEBUG) e.printStackTrace();
        throw new SAXException(e);
      }
    }
docs: co_entry_pause is called in startDocument() before anything else
  happens. It causes the filter to wait for a "go ahead" request
  from the controller before delivering any events. Note that
  the very first thing the controller tells us may be "I don't
  need events after all"!