anchor.diff:  -type request() :: term().
   -type state() :: #state{}.
   -type cached_token_map() ::
  -    #{reference() => {datastore_links_iter:token(), erlang:timestamp()}}. % @TODO VFS-7014 switch to unified time API
  +    #{reference() => {datastore_links_iter:token(), countdown_timer:instance()}}.
   -type is_failover_request() :: boolean(). % see ha_datastore.hrl for failover requests description
   -type remote_requests_processing_mode() :: ?HANDLE_LOCALLY | ?DELEGATE | ?IGNORE. % remote documents processing modes
                                                                            % (see datastore_protocol.hrl)
  
positive.code:     master_pid = Pid,
      keys_in_flush = KIF,
      keys_to_expire = ToExpire,
      flush_times = FT
  }) ->
      NewKeys = maps:merge(NotFlushed, CachedKeys),
  
      Timestamp = os:timestamp(), % @TODO VFS-7014 switch to unified time API
      {KIF2, FT2, Flushed} = case application:get_env(?CLUSTER_WORKER_APP_NAME, tp_fast_flush, on) of
          on ->
              Filtered = maps:filter(fun(_K, {V, _}) ->
  
negative.code:         _ -> CurrentRef
      end,
  
      StopWatch = stopwatch:start(),
      ToExpire2 = maps:fold(fun
          (K, {_, #{expiry := Expiry, disc_driver := undefined}}, Acc)
              when Expiry > 0 ->
              % Save expiry to compare with StopWatch in future
              maps:put(K, {StopWatch, Expiry}, Acc);
          (_, _, Acc) ->
              Acc
      end, ToExpire, Flushed),
  