anchor.diff:  
   
   -spec handle_cast(term(), #state{}) -> {noreply, #state{}}.
  +handle_cast({prepare_qbuf_dir, ok}, State) ->
  +    {noreply, State#state{status = ready}};
  +handle_cast({prepare_qbuf_dir, {error, Reason}}, State) ->
  +    {noreply, State#state{status = {init_failed, Reason}}};
   handle_cast(tick, State) ->
       do_reap_expired_qbufs(State);
   handle_cast(_Msg, State) ->
  
positive.code:     %% don't bother recovering any leftover tables
      case riak_kv_ts_util:rm_rf(RootPath) of
          ok ->
              ok;
          {error, Reason1} ->
              lager:warning("Found old data in qbuf dir \"~s\" could not be removed: ~p", [RootPath, Reason1]),
              not_quite_but_what_else_can_we_do
              %% eleveldb:open may fail, users beware
      end,
      case filelib:ensure_dir(RootPath) of
          ok ->
              ok;
          {error, Reason2} ->
              lager:warning("Could not create qbuf dir \"~s\": ~p", [RootPath, Reason2]),
              {error, qbuf_create_root_dir}
      end.
  
  schedule_tick() ->
  
negative.code:          }).
  
  -record(state, {
            status :: init_in_progress | {init_failed, Reason::term()} | ready,
            qbufs = [] :: [{qbuf_ref(), #qbuf{}}],
            total_size = 0 :: non_neg_integer(),
            %% no new queries; accumulation allowed
  