anchor.diff:  
   init([Partition]) -> {ok, #s{partition = Partition}}.
   
  +%% Publish
  +handle_command({publish, ReqId, Payload}, _Sender, State = #s{tail = Tail, log = Log}) ->
  +    NewState = State#s{log = [Payload|Log], tail = Tail + 1},
  +    {reply, {ok, ReqId}, NewState};
  +
  +%% Bind
   handle_command({bind, ReqId, Binding}, _Sender, State = #s{bindings = Bindings}) ->
       NewState = State#s{bindings = gb_sets:add(Binding, Bindings)},
       {reply, {ok, ReqId, {State#s.head, State#s.tail}}, NewState};
  +
  +%% Unbind
   handle_command({unbind, ReqId, Binding}, _Sender, State = #s{bindings = Bindings}) ->
       NewState = State#s{bindings = gb_sets:delete_any(Binding, Bindings)},
       {reply, {ok, ReqId}, NewState};
  +
  +%% Bindings
   handle_command({bindings, ReqId}, _Sender, State) ->
       {reply, {ok, ReqId, gb_sets:to_list(State#s.bindings)}, State};
  +
  +%% Ping
   handle_command(ping, _Sender, State) ->
       {reply, {pong, State#s.partition}, State}.
   
  
positive.code: 
  -spec publish(binary(), binary()) -> ok.
  %% @doc
  publish(_Topic, _Payload) ->
      %% Write the payload to the topic and then the vnodes call
      %% queue:handle_publish offset reply
      ok.
  
  -spec bind(binary(), binary()) -> {ok, non_neg_integer(), non_neg_integer()}.
  %% @doc
  
negative.code: %% Types
  %%
  
  -record(s, {partition = 0               :: non_neg_integer(),
              head      = 0               :: non_neg_integer(),
              tail      = 0               :: non_neg_integer(),
              bindings  = gb_sets:empty() :: gb_set(),
              log       = []              :: [binary()]}).
  
  -define(TIMEOUT, 5000).
  
  