anchor.diff:      sets:is_element(Peer, Passive).
   
   %% @private
  +add_to_pending(Peer, Pending) ->
  +    sets:add_element(Peer, Pending).
  +
  +%% @private
   remove_from_pending(Peer, Pending) ->
  -    lists:delete(Peer, Pending).
  +    sets:del_element(Peer, Pending).
   
   %% @private
   is_in_active_view(Peer, Active) ->
  
positive.code: 
      Actor = gen_actor(),
      {Active, Passive} = maybe_load_state_from_disk(Actor),
      Connections = dict:new(),
      Suspected = sets:new(),
  
      {ok, #state{pending=[],
                  active=Active,
                  passive=Passive,
                  suspected=Suspected,
  
negative.code:             #state{pending=Pending0,
                     connections=Connections0}=State) ->
      %% Add to list of pending connections.
      Pending = add_to_pending(Peer, Pending0),
  
      %% Trigger connection.
      Connections = maybe_connect(Peer, Connections0),
  