anchor.diff:  
   -compile(export_all).
   
  --record(mbox, {addr, pid, history}).
  +-record(mbox, {addr, pid}).
   -record(dmgr, {curr % A dict of all the currently active, alive mboxes.
                  }).
   
  
positive.code: 
  %% gen_server implementation.
  
  init([]) -> {ok, #dmgr{curr = dict:new()}}.
  terminate(_Reason, _DMgr) -> ok.
  code_change(_OldVn, DMgr, _Extra) -> {ok, DMgr}.
  handle_info(_Info, DMgr) -> {noreply, DMgr}.
  handle_cast(_Msg, DMgr) -> {noreply, DMgr}.
  
  handle_call({pid, Addr}, _From, DMgr) ->
  
negative.code: 
  create_mbox(Addr) ->
      {ok, Pid} = start_link(Addr),
      #mbox{addr = Addr, pid = Pid}.
  
  %% Child/worker process implementation, where we have one child/worker
  %% process per downstream Addr or MBox.  Note, this can be a
  