anchor.diff:  code_change(_OldVsn, State, _Extra) ->
       {ok, State}.
   
  +combine_stats(N, New, Existing) ->
  +    dict:merge(fun val_sum/3,
  +               dict:filter(fun classify/2, ringdict:to_dict(N, New)),
  +               Existing).
  +
  +val_sum(_K, L1, L2) ->
  +    lists:zipwith(fun(V1, V2) -> V1+V2 end, L1, L2).
  +
  +classify(K, _V) ->
  +     classify(K).
  +
  +classify("pid") -> false;
  +classify("uptime") -> false;
  +classify("time") -> false;
  +classify("version") -> false;
  +classify("pointer_size") -> false;
  +classify("rusage_user") -> false;
  +classify("rusage_system") -> false;
  +classify("tcpport") -> false;
  +classify("udpport") -> false;
  +classify("inter") -> false;
  +classify("verbosity") -> false;
  +classify("oldest") -> false;
  +classify("evictions") -> false;
  +classify("domain_socket") -> false;
  +classify("umask") -> false;
  +classify("growth_factor") -> false;
  +classify("chunk_size") -> false;
  +classify("num_threads") -> false;
  +classify("stat_key_prefix") -> false;
  +classify("detail_enabled") -> false;
  +classify("reqs_per_event") -> false;
  +classify("cas_enabled") -> false;
  +classify("tcp_backlog") -> false;
  +classify("binding_protocol") -> false;
  +classify(t) -> false;
  +classify(_) -> true.
  +
  +%
  +% API
  +%
  +
   received_data(T, Hostname, Port, Bucket, Stats) ->
       gen_server:cast(?MODULE, {received, T, Hostname, Port, Bucket, Stats}).
   
  
positive.code:          monitoring/3,
           received_data/5,
           unmonitoring/3,
           get_stats/4]).
  
  %% gen_server callbacks
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
  
negative.code: 
  get_stats(Hostname, Port, Bucket, Count) ->
      gen_server:call(?MODULE, {get, Hostname, Port, Bucket, Count}).
  
  get_stats(Bucket, Count) ->
      gen_server:call(?MODULE, {get, Bucket, Count}).
  