anchor.diff:  
   -ignore_xref([start_vnode/1]).
   
  --record(state, {partition, logs_map, clock, senders_awaiting_ack}).
  +-record(state, {partition, logs_map, clock, senders_awaiting_ack,
  +               last_read}).
   
   %% API
   -spec start_vnode(integer()) -> any().
  
positive.code:     {Current + 1, node()}.
  
  -ifdef(TEST).
  
  %% @doc Testing threshold_prune works as expected
  thresholdprune_test() ->
      Operations = [{log1, #operation{op_number=op1}},
                    {log1, #operation{op_number=op2}},
                    {log1, #operation{op_number=op3}},
                    {log1, #operation{op_number=op4}},
                    {log1, #operation{op_number=op5}}],
      Filtered = threshold_prune(Operations, op2),
      ?assertEqual([{log1, #operation{op_number=op3}},
                    {log1, #operation{op_number=op4}},
                    {log1, #operation{op_number=op5}}], Filtered).
  
  %% @doc Testing threshold_prune works even when there is no matching
  %%      op_id.
  thresholdprune_notmatching_test() ->
      Operations = [{log1, #operation{op_number=op1}},
                    {log1, #operation{op_number=op2}},
                    {log1, #operation{op_number=op3}},
                    {log1, #operation{op_number=op4}},
                    {log1, #operation{op_number=op5}}],
      Filtered = threshold_prune(Operations, op6),
      ?assertEqual([], Filtered).
  
  %% @doc Testing get_log_from_map works in both situations, when the key
  %%      is in the map and when the key is not in the map
  
negative.code: join_logs([], _F, Acc) ->
      Acc;
  join_logs([{_Preflist, Log}|T], F, Acc) ->
      JointAcc = fold_log(Log, start, F, Acc),
      join_logs(T, F, JointAcc).
  
  fold_log(Log, Continuation, F, Acc) ->
      case  disk_log:chunk(Log,Continuation) of 
          eof ->
              Acc;
          {Next,Ops} ->
              NewAcc = lists:foldl(F, Acc, Ops),
              fold_log(Log, Next, F, NewAcc)
      end.
  
  
  %% @doc insert_operation: Inserts an operation into the log only if the
  %%      OpId is not already in the log
  