anchor.diff:      {reply, Concurrency, State}.
   
   handle_cast({del_exclusion, {Mod, Idx}}, State=#state{excl=Excl}) ->
  -    Excl2 = ordsets:del_element({Mod, Idx}, Excl),
  +    Excl2 = sets:del_element({Mod, Idx}, Excl),
       {noreply, State#state{excl=Excl2}};
   
   handle_cast({add_exclusion, {Mod, Idx}}, State=#state{excl=Excl}) ->
  
positive.code: %%%===================================================================
  
  handle_call({get_exclusions, Module}, _From, State=#state{excl=Excl}) ->
      Reply =  [I || {M, I} <- ordsets:to_list(Excl), M =:= Module],
      {reply, {ok, Reply}, State};
  handle_call({add_outbound,Mod,Idx,Node,Pid},_From,State=#state{handoffs=HS}) ->
      case send_handoff(Mod,Idx,Node,Pid,HS) of
  
negative.code:     %% exclusion to ensure that an exiting node would eventually shutdown
      %% after all vnodes had finished handoff. This behavior is now handled
      %% by riak_core_vnode_manager:maybe_ensure_vnodes_started
      Excl2 = sets:add_element({Mod, Idx}, Excl),
      {noreply, State#state{excl=Excl2}};
  
  handle_cast({status_update, ModSrcTgt, StatsUpdate}, State=#state{handoffs=HS}) ->
  