anchor.diff:      handle_info(T, upgrade(S));
   
   handle_info(T, #listener{} = S) ->
  -    {noreply, #listener{} = l(T,S)}.
  +    {noreply, downgrade(#listener{} = l(T,S))}.
   
   %% upgrade/1
   
  
positive.code: %% any given time, implement both queues in the same ets table. The
  %% absolute value of the first element of the 2-tuple is the queue
  %% length, the sign says which queue it is.
  
  %% ---------------------------------------------------------------------------
  %% # code_change/3
  
negative.code:                                                count = K}
                                       = S) ->
      TPid = accept(Ref, Pid, S),
      {reply, {ok, TPid}, downgrade(S#listener{pending = {N-1,Q},
                                               count = K+1})};
  
  handle_call(_, _, State) ->
      {reply, nok, State}.
  