anchor.diff:  %%% Experiments
   %%%===================================================================
   
  +-ifdef(TEST).
  +
   run_local() ->
       run_local(10000).
   run_local(N) ->
  
positive.code:          destroy/1,
           read_meta/2,
           write_meta/3,
           local_compare/2,
           compare/2,
           compare/3,
           top_hash/1,
           get_bucket/3,
           key_hashes/2,
  
negative.code: top_hash(State) ->
      get_bucket(1, 0, State).
  
  compare(Tree, Remote, AccFun, Acc) ->
      compare(1, 0, Tree, Remote, AccFun, Acc).
  
  -spec levels(hashtree()) -> pos_integer().
  levels(#state{levels=L}) ->
  