code: public synchronized void add(VisitState visitState) {
  		final boolean wasEntirelyBroken = isEntirelyBroken();
  		if (visitState.lastExceptionClass != null) brokenVisitStates++;
  		visitStates.add(visitState);
  		assert brokenVisitStates <= visitStates.size();
  		if (wasEntirelyBroken && ! isEntirelyBroken()) workbenchBroken.decrementAndGet();
  		if (! wasEntirelyBroken && isEntirelyBroken()) workbenchBroken.incrementAndGet();
  	}
docs: Adds the given visit state to the visit-state queue.
  
  <p>This method is used for deserialization only.
  
  @param visitState the visit state that must be added to the visit-state queue.
  @see PriorityQueue#add(Object)