android - Get run duration of running task

Question

After I get a list of running tasks, I can get almost any information I would need. However, I couldn't find how to get how long the task has been running. I even tried the metaData Bundle that gets returned with the ActivityInfo, but that is null even though I explicitly request it. Is this possible at all?

I get the list of tasks as follows:

ActivityManager am = (ActivityManager) getSystemService(Activity.ACTIVITY_SERVICE);
List<RunningTaskInfo> list = am.getRunningTasks(100);
PackageManager pm = getPackageManager();

for (RunningTaskInfo thisInfo : list) {
    try {
        ComponentName componentName = thisInfo.baseActivity;
        ActivityInfo activityInfo = pm.getActivityInfo(componentName, PackageManager.GET_META_DATA);

        // this is null for some reason
        Bundle metaData = activityInfo.applicationInfo.metaData;
    } catch (NameNotFoundException e) {
        Log.e("AppChecker", "Oops");
        e.printStackTrace();
    }
}