anchor.diff:  
       %% when
       prepare_rtransfer({Worker1, RtransferOpts1}, {Worker2, RtransferOpts2},
  -        ?TEST_FILE_UUID, Offset, DataSize, notify_fun(), on_complete_fun(self())
  -    ),
  -
  -    ?assertReceivedMatch({on_complete, {ok, SizeToFetch}}, ?TIMEOUT).
  +        ?TEST_FILE_UUID, Offset, DataSize, notify_fun(CounterPid), on_complete_fun(self())
  +    ),
  +
  +    ?assertReceivedMatch({on_complete, {ok, SizeToFetch}}, ?TIMEOUT),
  +    stop_counter(CounterPid),
  +    ?assertReceivedMatch({counter, 6}, ?TIMEOUT).
   
   %%%===================================================================
   %%% SetUp and TearDown functions
  
positive.code:         error_open_fun_test,
          error_read_fun_test,
          error_write_fun_test,
          request_bigger_than_file_test,
          offset_greater_than_file_size_test
      ].
  
  -define(FILE_HANDLE, <<"file_handle">>).
  
negative.code:     Offset = DataSize div 3,
      SizeToFetch = DataSize - Offset,
      DataCounterPid = spawn(?MODULE, data_counter, [SizeToFetch]),
      CounterPid = spawn(?MODULE, counter, [0]),
  
      WriteFunOpt = {write_fun,
          fun(_Handle, _Offset, Data) ->
  