自己创建的featurelayer中为何无graphics属性？

根据官网中的代码此处为官网代码
https://developers.arcgis.com/javascript/3/jssamples/layers_feature.html
新建FeatureLayer

然后添加了几行代码想访问其Graphics
结果在网页上，FeatureLayer能够进行显示，但是在Chrome上设置断点调试，却发现FeatureLayer里面无Graphics属性。
具体代码如下

<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">

<title>FeatureLayer</title>



<link rel="stylesheet" href="https://js.arcgis.com/3.24/esr ... gt%3B

<script src="https://js.arcgis.com/3.24/%26 ... gt%3B



<style>

html, body, #map {

  padding: 0;

  margin: 0;

  height: 100%;

  width: 100%;

}

</style>



<script>

require([

    "esri/map",

    "esri/layers/FeatureLayer",

		 "esri/tasks/FeatureSet",

    "dojo/domReady!"

  ],

  function(

    Map,

    FeatureLayer,

		FeatureSet

  ) {



    var map = new Map("map", {

      basemap: "hybrid",

      center: [-82.44109, 35.6122],

      zoom: 17

    });



    /****************************************************************

     * Add feature layer - A FeatureLayer at minimum should point

     * to a URL to a feature service or point to a feature collection 

     * object.

     ***************************************************************/



    // Carbon storage of trees in Warren Wilson College.

    var featureLayer = new FeatureLayer("https://services.arcgis.com/V6 ... 6quot;);



    map.addLayer(featureLayer);

		

		var fs1 = new FeatureSet();



    for (var i = 0; i < featureLayer.graphics.length; i++) {

              fs1.features.push(featureLayer.graphics[i]);

              alert('graphic');

    }



  });

</script>

</head>



<body></body>



</html>