anchor.diff:  handle_info(start_heartbeat, #state{heartbeat_interval = Interval,
                                       node_name = NodeName} = State) ->
       lager:info("Starting heartbeat: [~s] (interval ~ws)", [NodeName, Interval]),
  -    folsom_metrics:new_histogram(?INTERVAL_METRIC),
       timer:apply_interval(Interval, ?MODULE, heartbeat, [self()]),
       {noreply, State#state{heartbeat_timestamp = pushy_time:timestamp()}};
   handle_info({zmq, Sock, Frame, [rcvmore]}, State) ->
  
positive.code: -include_lib("pushy_common/include/pushy_metrics.hrl").
  -include_lib("public_key/include/public_key.hrl").
  
  -define(INTERVAL_METRIC, <<"heartbeat.interval">>).
  
  %% ------------------------------------------------------------------
  %% API Function Exports
  
negative.code:     % Send Header (including signed checksum)
      HeaderFrame = pushy_messaging:make_header(proto_v2, SessionMethod, SessionKey, BodyFrame),
      Now = pushy_time:timestamp(),
      folsom_metrics:notify(?INTERVAL_METRIC, pushy_time:diff_in_secs(LastTimestamp, Now), histogram),
      pushy_messaging:send_message(Sock, [HeaderFrame, BodyFrame]),
      lager:debug("Heartbeat sent: ~s,sequence=~p",[NodeName, Sequence]),
      State#state{sequence=Sequence + 1,
  