anchor.diff:  %% %%%%%%%%%%%%%%%%%%%%%%%%%
   %% functions for abort_write
   %% %%%%%%%%%%%%%%%%%%%%%%%%%
  -%% abort write releases the write lock of a given entry, if it was
  -%% set.
  -
  -%% erlang shell test call: api_tx:write("a", 1).
  -
   -spec abort_write_feeder(tx_tlog:tlog_entry_write(), ?RT:key(), ok,
                             prbr:r_with_id(), {txid_on_cseq:txid(), version()}) ->
                                    {tx_tlog:tlog_entry_write(), ?RT:key(),
  
positive.code: commit_read_feeder(TLogEntry, TxId, ok, Round, OldVal) ->
      {TLogEntry, TxId, self(), Round, OldVal}.
  
  -spec commit_read(tx_tlog:tlog_entry(), ?RT:key(), comm:erl_local_pid(),
                    prbr:r_with_id(), any()) -> ok.
  commit_read(TLogEntry, TxId, ReplyTo, NextRound, OldVal) ->
  
negative.code: %% %%%%%%%%%%%%%%%%%%%%%%%%%
  %% functions for commit_read
  %% %%%%%%%%%%%%%%%%%%%%%%%%%
  -spec commit_read_feeder(tx_tlog:tlog_entry(), ?RT:key(), ok,
                           prbr:r_with_id(), {txid_on_cseq:txid(), version()}) ->
                                  {tx_tlog:tlog_entry(),
  