anchor.diff:  -export([
       child_spec/2,
       start_link/2,
  -    find_or_make_filename_from_prefix/2,
  +    find_or_make_filename_from_prefix/3,
       increment_prefix_sequence/2,
       list_files_by_prefix/2
       ]).
  
positive.code: maybe_cleanup(Tid, Key, true) ->
      true = ets:delete(Tid, Key).
  
  
  -ifdef(TEST).
  
  
negative.code:     ]).
  
  -define(TIMEOUT, 10 * 1000).
  -include("machi_projection.hrl"). %% included for pv1_epoch_n type
  
  -record(state, {fluname :: atom(),
                  tid     :: ets:tid(),
                  datadir :: file:dir(),
                  epoch   :: pv1_epoch_n()
                 }).
  
  %% public API
  