anchor.diff:    case gun:await_body(Conn, Ref, Timeout) of
       {ok, Body} ->
         {Body2, Req2, HandlerState} = call(Req, State, res_body, Body),
  -      ok = cowboy_req:chunk(Body2, Req2),
  -      terminate(Req, State#state{handler_state = HandlerState});
  +      send(Req2, State#state{handler_state = HandlerState}, Body2, fun terminate/2);
       {error, timeout} ->
         next(Req, State, 504);
       {error, Reason} ->
  
positive.code:       no_call
    end.
  
  exported(_Req, _State = #state{handler = Handler}, Callback, Arity) ->
    erlang:function_exported(Handler, Callback, Arity).
  
  
negative.code: chunk_res_body(Req, State = #state{conn = Conn, ref = Ref, timeout = Timeout}) ->
    case gun:await(Conn, Ref, Timeout) of
      {data, nofin, Data} ->
        send(Req, State, Data, fun chunk_res_body/2);
      {data, fin, Data} ->
        send(Req, State, Data, fun terminate/2);
      {error, timeout} ->
        next(Req, State, 504);
      {error, Reason} ->
  