anchor.diff:          undefined -> ok;
           File -> file:write(File, Packet)
       end,
  -    ok = gen_tcp:send(State#state.upstream, Packet),
  +    State#state.upstream_sender ! Packet,
       State.
   
   
  
positive.code: -record(state, {bad_vbucket_count = 0 :: non_neg_integer(),
                  upstream :: port(),
                  downstream :: port(),
                  upbuf = <<>> :: binary(),
                  downbuf = <<>> :: binary(),
                  vbuckets,
  
negative.code:         false ->
              {noreply, State}
      end;
  handle_info({'EXIT', Pid, Reason}, #state{upstream_sender = SenderPid} = State) when Pid =:= SenderPid ->
      ?log_error("killing myself due to unexpected upstream sender exit with reason: ~p", [Reason]),
      {stop, {unexpected_upstream_sender_exit, Reason}, State};
  handle_info(Msg, State) ->
      ?log_info("handle_info(~p, ~p)", [Msg, State]),
      {noreply, State}.
  