我想饼图动画在加载我是怎么做的？(我是指谷歌可视化API )

<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>

<div id="chart_div"></div>

google.charts.load('current', {'packages':['corechart']});
google.charts.setOnLoadCallback(drawChart);

function drawChart() {
  var data = new google.visualization.DataTable();
  data.addColumn('string', 'Category');
  data.addColumn('number', 'Value');
  data.addRows([
    ['Category 1', 10],
    ['Category 2', 20],
    ['Category 3', 30]
  ]);

  var options = {
    animation: {
      duration: 1000,
      easing: 'out',
      startup: true
    }
  };

  var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
  chart.draw(data, options);
}