anchor.diff:    [] = barrel_httpc_changes:changes(Pid),
     Doc2 = #{ <<"id">> => <<"bb">>, <<"v">> => 1},
     {ok, <<"bb">>, _} = barrel_httpc:post(db(Config), Doc2, []),
  -  {ok, _} = barrel_httpc:get(db(Config), <<"bb">>, []),
  +  {ok, _, _} = barrel_httpc:get(db(Config), <<"bb">>, []),
     timer:sleep(100),
     [#{ <<"seq">> := 2, <<"id">> := <<"bb">>}] = barrel_httpc_changes:changes(Pid),
     [] = barrel_httpc_changes:changes(Pid),
  
positive.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, []),
  
negative.code:     #{ <<"seq">> := 3, <<"id">> := <<"cc">>},
      #{ <<"seq">> := 4, <<"id">> := <<"dd">>}
    ] = barrel_httpc_changes:changes(Pid),
  
    ok = barrel_httpc_changes:stop(Pid).
  
  changes_feed_callback(Config) ->
  