anchor.diff:  	case call(Req, State, Callback) of
   		no_call ->
   			next(Req, State, OnTrue);
  -		{Expected, Req2, HandlerState2} ->
  -			next(Req2, State#state{handler_state=HandlerState2}, OnTrue);
  -		{_Unexpected, Req2, HandlerState2} ->
  -			next(Req2, State#state{handler_state=HandlerState2}, OnFalse)
  +		{Expected, Req2, HandlerState} ->
  +			next(Req2, State#state{handler_state=HandlerState}, OnTrue);
  +		{_Unexpected, Req2, HandlerState} ->
  +			next(Req2, State#state{handler_state=HandlerState}, OnFalse)
   	end.
   
   call(Req, #state{handler=Handler, handler_state=HandlerState}, Fun) ->
  
positive.code: 	case call(Req, State, content_types_accepted) of
  		no_call ->
  			respond(Req, State, 415);
  		{CTA, Req2, HandlerState2} ->
  			State2 = State#state{handler_state=HandlerState2},
  			{ContentType, Req3}
  				= cowboy_http_req:parse_header('Content-Type', Req2),
  			choose_content_type(Req3, State2, OnTrue, ContentType, CTA)
  
negative.code: 	case call(Req, State, last_modified) of
  		no_call ->
  			{undefined, Req, State#state{last_modified=no_call}};
  		{LastModified, Req2, HandlerState} ->
  			{LastModified, Req2, State#state{handler_state=HandlerState,
  				last_modified=LastModified}}
  	end;
  last_modified(Req, State=#state{last_modified=LastModified}) ->
  