anchor.diff:  
   upstream_sender_loop(Upstream) ->
       receive
  -        {'$gen_call', From, silence_upstream} ->
  -            gen_server:reply(From, ok),
  +        {silence_upstream_new_style, Pid} ->
  +            Pid ! upstream_silenced,
               erlang:hibernate(erlang, exit, [silenced]);
           Data ->
               ok = gen_tcp:send(Upstream, Data)
  
positive.code:                     end;
                  <<?TAP_OPAQUE_VB_FILTER_CHANGE_COMPLETE:32>> ->
                      started = VBFilterChangeState,
                      NewState = State2#state{vb_filter_change_state=completed},
                      {stop, NewState};
                  _Other ->
                      {ok, State2}
  
negative.code: 
  complete_native_vb_filter_change(#state{downstream=Downstream,
                                          upstream=Upstream,
                                          vb_filter_change_state=ChangeState,
                                          vb_filter_change_owner=Owner} = State) ->
      completed = ChangeState,
  