anchor.diff:  -spec(fetch(Id::atom(), KeyBin::binary(), Fun::function()) ->
                {ok, list()} | not_found | {error, any()}).
   fetch(Id, KeyBin, Fun) ->
  -    gen_server:call(Id, {fetch, KeyBin, Fun}).
  +    gen_server:call(Id, {fetch, KeyBin, Fun}, ?DEF_TIMEOUT).
   
   
   %% @doc Retrieve a first record from backend-db.
  
positive.code: -spec(get_db_raw_filepath(atom()) ->
               ok | {error, any()}).
  get_db_raw_filepath(Id) ->
      gen_server:call(Id, {get_db_raw_filepath}).
  
  
  %%--------------------------------------------------------------------
  
negative.code: -spec(put(Id::atom(), KeyBin::binary(), ValueBin::binary()) ->
               ok | {error, any()}).
  put(Id, KeyBin, ValueBin) ->
      gen_server:call(Id, {put, KeyBin, ValueBin}, ?DEF_TIMEOUT).
  
  
  %% @doc Retrieve an object from backend-db.
  