anchor.diff:  	L when L#log.mode =:= read_only ->
   	    reply(From, {error, {read_only_mode, L#log.name}}, S);
   	L when L#log.status =:= ok ->
  -	    log_loop(S, From, [B], []);
  +	    log_loop(S, From, [B], [], iolist_size(B));
   	L when L#log.status =:= {blocked, false} ->
   	    reply(From, {error, {blocked_log, L#log.name}}, S);
   	L when L#log.blocked_by =:= From ->
  
positive.code: 	    notify_owners({read_only,B}),
  	    loop(S);
  	L when L#log.status =:= ok, L#log.format =:= internal ->
  	    log_loop(S, [], [B], []);
  	L when L#log.status =:= ok ->
  	    notify_owners({format_external, B}),
  	    loop(S);
  
negative.code: 	L when L#log.mode =:= read_only ->
  	    reply(From, {error, {read_only_mode, L#log.name}}, S);
  	L when L#log.status =:= ok, L#log.format =:= internal ->
  	    log_loop(S, From, [B], [], iolist_size(B));
  	L when L#log.status =:= ok, L#log.format =:= external ->
  	    reply(From, {error, {format_external, L#log.name}}, S);
  	L when L#log.status =:= {blocked, false} ->
  