anchor.diff:        no_call
     end.
   
  -call(Req, State=#state{handler=Handler, handler_state=HandlerState}, Callback, Arg) ->
  +call(Req, State = #state{handler = Handler, handler_state = HandlerState}, Callback, Arg) ->
     case erlang:function_exported(Handler, Callback, 3) of
       true ->
         try
  
positive.code:     {state, HandlerState}
    ]).
  
  proxy_terminate(Req, #state{handler=Handler, handler_state=HandlerState}) ->
    case erlang:function_exported(Handler, proxy_terminate, 2) of
      true -> ok = Handler:proxy_terminate(
        cowboy_req:lock(Req), HandlerState);
  
negative.code:     true ->
        try Handler:proxy_init(Req, HandlerOpts) of
          {ok, Req2, HandlerState} ->
            backend(Req2, #state{env = Env, method = Method, req_headers = filter_headers(Headers, []),
              handler = Handler, handler_state = HandlerState})
        catch Class:Reason ->
          error_terminate(Req, #state{handler = Handler, handler_state = HandlerOpts},
  