如何设置Web推送通知的BigPictureStyle？

// 订阅推送通知
navigator.serviceWorker.register('service-worker.js')
  .then(function(registration) {
    return registration.pushManager.subscribe({ userVisibleOnly: true });
  })
  .then(function(subscription) {
    // 生成推送通知内容的JSON对象
    var notificationData = {
      title: 'Web推送通知',
      content: '这是一个使用BigPictureStyle的推送通知',
      image: 'https://example.com/big_picture.jpg',
      icon: 'https://example.com/icon.png'
    };

    // 发送推送通知
    fetch('/send-notification', {
      method: 'POST',
      body: JSON.stringify(notificationData),
      headers: {
        'Content-Type': 'application/json'
      }
    });

    // 监听推送事件
    self.addEventListener('push', function(event) {
      var data = event.data.json();

      // 显示推送通知
      self.registration.showNotification(data.title, {
        body: data.content,
        icon: data.icon,
        image: data.image,
        actions: [
          { action: 'action1', title: 'Action 1' },
          { action: 'action2', title: 'Action 2' }
        ]
      });
    });
  });