anchor.diff:    [#{ <<"seq">> := 1, <<"id">> := <<"aa">>}] = barrel_httpc_changes:changes(Pid),
     [] = barrel_httpc_changes:changes(Pid),
     ok = barrel_httpc_changes:stop(Pid).
  -  
  +
   collect_changes(0, Q) ->
     queue:to_list(Q);
   collect_changes(I, Q) ->
     receive
       {change, Change} ->
         collect_changes(I-1, queue:in(Change, Q))
  -  end.+  end.
  
positive.code:     #{ <<"seq">> := 3, <<"id">> := <<"cc">>},
      #{ <<"seq">> := 4, <<"id">> := <<"dd">>}
    ] = barrel_httpc_changes:changes(Pid),
    
    ok = barrel_httpc_changes:stop(Pid).
  
  changes_feed_callback(Config) ->
  
negative.code:     end,
    Options = #{since => 0, mode => sse, changes_cb => Callback },
    {ok, Pid} = barrel_httpc_changes:start_link(db(Config), Options),
  
    Doc1 = #{ <<"id">> => <<"aa">>, <<"v">> => 1},
    Doc2 = #{ <<"id">> => <<"bb">>, <<"v">> => 1},
    {ok, <<"aa">>, _} = barrel_httpc:post(db(Config), Doc1, []),
  