anchor.diff:  %%      of the form {selected_data, Instance, ExchangeData}.
   -spec select_data(State::state()) -> {ok, state()}.
   select_data(State) ->
  +    %% cy_shuffle <=> gossip_trigger -> select_data()
       {ok, State}.
   
   
  
positive.code: %%      of them are ignored, as cyclon doesn't use / implements this features.
  -spec notify_change(_, _, State::state()) -> {ok, state()}.
  notify_change(_, _, State) ->
      {ok, State}.
  
  
  
negative.code: %%      Called by the gossip module upon {get_values_best} messages.
  -spec get_values_best(State::state()) -> {ok, state()}.
  get_values_best(State) ->
      %% use to implement get_subset_rand() api functions??
      {ok, State}.
  
  
  