How to check if still connected to the network set by setProcessDefaultNetwork()

I have the following code that sets the default network of my internet connection.

if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
    NetworkRequest.Builder builder = new NetworkRequest.Builder();
    builder.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
    builder.addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR);
    NetworkCallback networkCallback = new NetworkCallback() {
        @Override
        public void onAvailable(Network network) {
            boolean result = ConnectivityManager.setProcessDefaultNetwork(network);
            Log.d(TAG, "success? " + result);
        }
    };
    NetworkRequest networkRequest = builder.build();
    connMgr.requestNetwork(networkRequest, networkCallback);
    connMgr.registerNetworkCallback(networkRequest, networkCallback);
}

This works properly. However, later on, when I check using the following code:

ConnectivityManager connMgr = (ConnectivityManager)
    context.getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfo networkInfoMobile =
    connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

networkInfoMobile.isConnected();  // returns false!

This always returns false. What am I doing wrong?

What I did is I saved the network provided by onAvailable() callback. Then later, I checked the connectivity thru:

NetworkInfo networkInfo = connMgr.getNetworkInfo(networkFromOnAvailable);
networkInfo.isConnected();

Cheers!