anchor.diff:        next(Req2, State2, fun open_connection/2)
     end.
   
  +open_connection(Req, State = #state{backend = Conn}) when is_pid(Conn) ->
  +  next(Req, State#state{conn = Conn}, fun format_path/2);
   open_connection(Req, State = #state{backend = {Proto, Host, Port, _Path}, timeout = Timeout}) ->
     Opts = [
       {retry, fast_key:get(retry, State#state.env, 1)},
  
positive.code:   filter_headers(Headers, [Header|Acc]).
  
  %% TODO support more combos
  normalize_backend({Proto, Host, Port, Path}) ->
    {Proto, Host, Port, Path};
  normalize_backend({Proto, Host, Port}) when is_atom(Proto) andalso is_integer(Port) ->
  
negative.code:   {ok, Req2} = cowboy_req:reply(StatusCode, Req),
    terminate(Req2, State).
  
  terminate(Req, State = #state{env = Env, conn = Conn, backend = Conn}) ->
    proxy_terminate(Req, State),
    {ok, Req, [{result, ok}|Env]};
  terminate(Req, State = #state{env = Env, conn = Conn}) ->
    proxy_terminate(Req, State),
    ok = gun:close(Conn),
  