anchor.diff:          ]).
   
   -export([ rows/2        %% incoming rows          [RowList,true] | [RowList,false] | [RowList,tail]    RowList=list(KeyTuples)
  +        , delete/2      %% delete row event
           , rows_limit/3  %% limit of the rows that can be fetched in one request to the driver
           , gui_req/4     %% button <<"Button">> =  <<">">>
                           %%                        <<"|<">>
  
positive.code: -spec rows_limit(integer(), list(), {atom(), pid()}) -> ok.
  rows_limit(NRows, Recs, {?MODULE, Pid}) ->
      gen_fsm:send_event(Pid, {rows_limit, {NRows, Recs}}).
  
  -spec fetch(atom(), atom(), #state{}) -> #state{}.
  fetch(FetchMode,TailMode, #state{bufCnt = Count, ctx = #ctx{fetch_recs_async_fun = Fraf}}=State0) ->
  
negative.code: %             State1 = data_append(tailing,{[Rec],tail},State0),
  %             {next_state, tailing, State1#state{pfc=0}}
  %     end;      
  tailing({delete, Tab,Key}, State) ->
      ?Info("tailing  -- row deleted ~p:~p~n", [Tab,Key]),
      {next_state, tailing, State};
  tailing({delete, Record}, State) ->
      ?Info("tailing  -- row deleted ~p~n", [Record]),
      {next_state, tailing, State};
  tailing({rows, {Recs,Complete}}, State0) ->
      % ?Info("tailing  -- row~n", []),
      State1 = data_append(tailing,{Recs,Complete},State0),
  