当设置setGroupSummary时，为什么Android O中的通知徽章不显示？

NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
String channelId = "your_channel_id";
CharSequence channelName = "Your Channel Name";
int importance = NotificationManager.IMPORTANCE_DEFAULT;
NotificationChannel channel = new NotificationChannel(channelId, channelName, importance);
channel.setShowBadge(true); // 启用徽章显示
notificationManager.createNotificationChannel(channel);

NotificationCompat.Builder builder = new NotificationCompat.Builder(context, channelId)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("Your Title")
        .setContentText("Your Text")
        .setGroup("your_group_key")
        .setGroupSummary(true); // 设置为组摘要通知