anchor.diff:  
   %% @type Req -> #httpd{} | {json_req, JsonObj()}
   handle_changes(#changes_args{style=Style}=Args1, Req, Db) ->
  -    Args = Args1#changes_args{filter=
  -            make_filter_fun(Args1#changes_args.filter, Style, Req, Db)},
  +    #changes_args{feed = Feed} = Args = Args1#changes_args{
  +        filter = make_filter_fun(Args1#changes_args.filter, Style, Req, Db)
  +    },
       StartSeq = case Args#changes_args.dir of
       rev ->
           couch_db:get_update_seq(Db);
       fwd ->
           Args#changes_args.since
       end,
  -    if Args#changes_args.feed == "continuous" orelse
  -        Args#changes_args.feed == "longpoll" ->
  -        fun(Callback) ->
  +    if Feed == "continuous" orelse Feed == "longpoll" ->
  +        fun(CallbackAcc) ->
  +            {Callback, UserAcc} = get_callback_acc(CallbackAcc),
               Self = self(),
               {ok, Notify} = couch_db_update_notifier:start_link(
                   fun({_, DbName}) when DbName == Db#db.name ->
  
positive.code: deleted_item(_) -> [].
  
  % waits for a db_updated msg, if there are multiple msgs, collects them.
  wait_db_updated(Timeout, TimeoutFun) ->
      receive db_updated -> get_rest_db_updated()
      after Timeout ->
          case TimeoutFun() of
          ok -> wait_db_updated(Timeout, TimeoutFun);
          stop -> stop
          end
      end.
  
  get_rest_db_updated() ->
      receive db_updated -> get_rest_db_updated()
      after 0 -> updated
      end.
  
negative.code:     Go = if Limit =< 1 -> stop; true -> ok end,
      case Results of
      [] ->
          {Go, {Db, Seq, nil, FilterFun, Callback, UserAcc, "continuous", Limit,
                  IncludeDocs}
          };
      _ ->
          ChangesRow = changes_row(Db, Seq, Id, Del, Results, Rev, IncludeDocs),
          UserAcc2 = Callback({change, ChangesRow, <<>>}, "continuous", UserAcc),
          {Go, {Db, Seq, nil, FilterFun, Callback, UserAcc2, "continuous",
                  Limit - 1, IncludeDocs}
          }
      end;
  changes_enumerator(DocInfo, {Db, _, Prepend, FilterFun, Callback, UserAcc,
      ResponseType, Limit, IncludeDocs}) ->
  
      #doc_info{id=Id, high_seq=Seq, revs=[#rev_info{deleted=Del,rev=Rev}|_]}
          = DocInfo,
  