anchor.diff:      rrd().
   create(SlotLength, Count, Type) ->
       create(SlotLength, Count, Type, os:timestamp()).
  -
  --spec create_timed(SlotLength::timespan(), Count::pos_integer(), Type::timeseries_type(),
  -                   StartTime::time()) -> rrd().
  -create_timed(SlotLength, Count, Type, {_,_,_} = StartTime) ->
  -    create(SlotLength, Count, Type, StartTime).
   
   % @doc Note: gauge, counter and timing types accept only number() as value, event
   %      accepts any value.
  
positive.code: -endif.
  
  % external API with transparent time handling
  -export([create/3, create_timed/4,
           add_now/2, check_timeslot_now/1,
           merge/2,
           dump/1, dump_with/2, dump_with/3]).
  
negative.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %
  % External API without transparent time handling and some internal API
  %
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  %@doc StepSize in milliseconds
  