anchor.diff:  
   -record(state, {ref :: reference(),
                   data_root :: string(),
  +                open_opts = [],
                   config :: config(),
                   read_opts = [],
                   write_opts = [],
  
positive.code: %% @doc Delete all objects from this eleveldb backend
  %% and return a fresh reference.
  -spec drop(state()) -> {ok, state()} | {error, term(), state()}.
  drop(#state{data_root=DataRoot}=State) ->
      case eleveldb:destroy(DataRoot, []) of
          ok ->
              case open_db(DataRoot, State#state.config) of
                  {ok, Ref, FinalConfig} ->
                      {ok, State#state { ref = Ref, config = FinalConfig }};
                  {error, Reason} ->
                      {error, Reason, State}
              end;
          {error, Reason} ->
              {error, Reason, State}
      end.
  
  %% @doc Returns true if this eleveldb backend contains any
  
negative.code: %% ===================================================================
  
  %% @private
  init_state(DataRoot, Config) ->
      %% Get the data root directory
      filelib:ensure_dir(filename:join(DataRoot, "dummy")),
  
  