anchor.diff:      %% signal vb replicator
       Pid ! Signal,
   
  -    ?xdcr_debug("grant one token to rep (pid: ~p, targetnode: ~p), available tokens: ~p (total tokens: ~p)",
  -                [Pid, TargetNode, NewCount, TotalTokens]),
  +    ?log_debug("grant one token to rep (pid: ~p, targetnode: ~p), available tokens: ~p (total tokens: ~p)",
  +               [Pid, TargetNode, NewCount, TotalTokens]),
   
       NewState = State#concurrency_throttle_state{
                    avail_tokens = NewCount,
  
positive.code:                                 monitor_dict = MonDict} = State,
      case dict:size(WaitingPool) of
          0 ->
              ?xdcr_debug("nothing to schedule, # of active reps: ~p, # of acrtive target nodes: ~p",
                          [dict:size(ActivePool), dict:size(TargetLoad)]),
              State;
          _ ->
              {WaitingPid, Signal, TargetNode} = choose_pid_to_schedule(WaitingPool,
  
negative.code:             NewAvailTokens = NewTokens - dict:size(ActivePool),
              State1 =  State#concurrency_throttle_state{total_tokens = NewTokens,
                                                         avail_tokens = NewAvailTokens},
              ?log_debug("number of total tokens changes from ~p to ~p, "
                         "number of available tokens changes from  ~p to ~p, reported by replicator: ~p",
                         [TotalTokens, NewTokens, AvailTokens, NewAvailTokens,Pid]),
  
              %% schedule more jobs if we have more available tokens
              NewState = if
                             NewAvailTokens > 0 ->
                                 ?log_debug("Will signal ~p process to proceed", [NewAvailTokens]),
                                 signal_waiting(State1, NewAvailTokens);
                             NewAvailTokens < 0 ->
                                 ?log_debug("Will ask ~p processes to return token back", [-NewAvailTokens]),
                                 ask_to_return_token(dict:to_list(ActivePool), -NewAvailTokens),
                                 State1;
                             NewAvailTokens =:= 0 ->
  