anchor.diff:  %% State record.
   -record(state, {store :: store()}).
   
  +%% Broadcast record.
  +-record(broadcast, {id :: id(), type :: type(), value :: value()}).
  +
   %% Definitions for the bind/read fun abstraction.
   -define(BIND, fun(_AccId, _AccValue, _Store) ->
                   ?CORE:bind(_AccId, _AccValue, _Store)
  
positive.code: 
  %% @todo doc
  %% @todo spec
  broadcast_data(Msg) ->
      Id = druuid:v4(),
      lager:warning("id: ~p, msg: ~p", [Id, Msg]),
      {Id, Msg}.
  
  %% @todo doc
  %% @todo spec
  merge(Id, Msg) ->
      lager:warning("id: ~p, msg: ~p", [Id, Msg]),
      false.
  
  %% @todo doc
  %% @todo spec
  is_stale(Id) ->
      lager:warning("id: ~p", [Id]),
      true.
  
  %% @todo doc
  %% @todo spec
  
negative.code: %%      {@link declare/0}) dataflow variable.  The `Value' provided is
  %%      the value to bind.
  %%
  -spec bind(id(), value()) -> {ok, var()}.
  bind(Id, Value) ->
      {ok, Result} = gen_server:call(?MODULE, {bind, Id, Value}, infinity),
      broadcast(Result),
      {ok, Result}.
  
  %% @doc Bind a dataflow variable to another dataflow variable.
  %%
  