anchor.diff:  
   system_continue(_, _, {wait_retry, State}) ->
     wait_retry(State);
  +system_continue(_, _, {wait_response, State}) ->
  +  wait_response(State);
   system_continue(_, _, {wait_changes, State}) ->
     wait_changes(State).
   
  
positive.code:   receive
      connect ->
        init_feed(State);
      {system, From, Request} ->
        sys:handle_system_msg(
          Request, From, Parent, ?MODULE, [],
          {wait_retry, State})
    end.
  
  wait_response(#state{ ref = Ref, options = Options}=State) ->
    receive
      {hackney_response, Ref, {status, 200, _}} ->
        Conn = State#state.conn,
  
negative.code:   ).
  
  init(Parent, Conn, Options) ->
    process_flag(trap_exit, true),
    proc_lib:init_ack(Parent, {ok, self()}),
    %% initialize the state
    State = #state{ parent = Parent,
  