anchor.diff:  
   -export([
     collect_change/1,
  +  include_doc/1,
     collect_changes/1,
     changes_feed_callback/1,
     heartbeat_collect_change/1
  
positive.code: all() ->
    [
      collect_change,
      collect_changes,
      changes_feed_callback,
      heartbeat_collect_change
  
negative.code:   [] = barrel_httpc_changes:changes(Pid),
    ok = barrel_httpc_changes:stop(Pid).
  
  include_doc(Config) ->
    {ok, Pid} = barrel_httpc_changes:start_link(db(Config), #{since => 0, mode => sse, include_doc => true}),
    [] = barrel_httpc_changes:changes(Pid),
    Doc = #{ <<"id">> => <<"aa">>, <<"v">> => 1},
    {ok, <<"aa">>, _RevId} = barrel_httpc:put(db(Config), Doc, []),
    timer:sleep(100),
    [#{ <<"seq">> := 1, <<"id">> := <<"aa">>, <<"doc">> := Doc2}] = barrel_httpc_changes:changes(Pid),
    #{ <<"id">> := <<"aa">>, <<"v">> := 1 } =  Doc2,
    [] = barrel_httpc_changes:changes(Pid),
    ok = barrel_httpc_changes:stop(Pid).
  
  collect_changes(Config) ->
    {ok, Pid} = barrel_httpc_changes:start_link(db(Config), #{since => 0, mode => sse}),
    [] = barrel_httpc_changes:changes(Pid),
  