anchor.diff:      try
           #{handle_event := HandleEvent,
             headers := Headers} = process_options(Options, Headers0, delete),
  -        Event = {delete, {Url, Headers}},
  +        Event = {delete, {Url, Headers, []}},
           StreamRef = gen_fsm:sync_send_event(Pid, Event),
           {ok, StreamRef}
       catch
  
positive.code: 
      Event = case IsAsync of
                  true ->
                      {get_async, {HandleEvent, AsyncMode}, {Url, Headers}};
                  false ->
                      {get, {Url, Headers}}
             end,
      StreamRef = gen_fsm:sync_send_event(Pid, Event),
      {ok, StreamRef}.
  
negative.code:     try
          #{handle_event := HandleEvent,
            headers := Headers} = process_options(Options, Headers0, head),
          Event = {head, {Url, Headers, []}},
          StreamRef = gen_fsm:sync_send_event(Pid, Event),
          {ok, StreamRef}
      catch
  