anchor.diff:                  callback_failures = Fails, interval_tref = Tref},
               {ok, waiting, OutCheck};
           true ->
  -            % likely a late message, or a faker
  -            {ok, suspend, InCheck#health_check{checking_pid = undefined, callback_failures = Fails}}
  +            %% likely a late message, or a faker
  +            {ok, suspend, InCheck#health_check{checking_pid = undefined,
  +                                               callback_failures = Fails}}
       end;
   
   %% message handling when in a waiting state
  
positive.code:     Fails = InCheck#health_check.callback_failures + 1,
      if
          Fails == InCheck#health_check.max_callback_failures ->
              lager:error("health check callback for ~p failed too many times, disabling.", [Service]),
              {down, suspend, InCheck#health_check{checking_pid = undefined, callback_failures = Fails}};
          Fails < InCheck#health_check.max_callback_failures ->
              #health_check{health_failures = N, check_interval = Inter} = InCheck,
              Tref = next_health_tref(N, Inter, Service), 
  
negative.code: 
  -behaviour(gen_server).
  
  -define(DEFAULT_HEALTH_CHECK_INTERVAL, 60000).
  %% API
  -export([start_link/0,
           service_up/2,
  