Measuring UDP speed

Question

How do I accurately measure the data rate of the router by using UDP?

My reference is Wi-Fi SweetSpots it measures the data transfer rate of the router locally (not internet speed)

Here's my code now, I'm getting around 700mbs to 800mbs (which is not correct)

public class RouterTransferRateService extends DaggerService {
    public static final String ACTION_NAME = "rounter.transter.data.service";

    @Inject
    WifiManager wifiManager;

    @Inject
    WirelessInfoProvider wirelessInfoProvider;

    private final IBinder binder = new RouterTransferRateDataBinder();

    private TimerTask taskReceive;
    private Timer timerReceive;
    private boolean isSending = false;
    private boolean isReceiving = false;

    private final int BUF_SIZE = 65507;
    private final int serverPort = 50001;
    private final long MB = 1024L * 1024L;
    private long oldBytes = 0;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return START_STICKY;
    }

    private void initializeTimerTask() {

        taskReceive = new TimerTask() {
            @Override
            public void run() {
                long currentBytes = TrafficStats.getUidRxBytes(myUid());
                long bytesPerSec = currentBytes - oldBytes;
                oldBytes = currentBytes;


                Log.e("Data Rate?", (bytesPerSec / MB) + "Mbps");
            }
        };

        new Thread(() -> {
            try {
                DatagramSocket senderSocket = new DatagramSocket();
                senderSocket.setSendBufferSize(BUF_SIZE);
                byte[] buf = new byte[BUF_SIZE];

                InetAddress address = wirelessInfoProvider.getInetAddress();
                new Random().nextBytes(buf);

                while (isSending) {
                    try {
                        DatagramPacket packet = new DatagramPacket(buf, buf.length, address, serverPort);
                        senderSocket.send(packet);
                    } catch (Exception e) {

                    }
                }
                senderSocket.disconnect();
                senderSocket.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }).start();

        new Thread(() -> {
            try {
                DatagramSocket receiverSocket = new DatagramSocket(serverPort);
                receiverSocket.setReceiveBufferSize(BUF_SIZE);
                byte[] buffer = new byte[BUF_SIZE];
                DatagramPacket packet = new DatagramPacket(buffer, BUF_SIZE);

                while (isReceiving) {
                    receiverSocket.receive(packet);
                }
                receiverSocket.disconnect();
                receiverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }).start();
    }

    private void startTimer() {
        isSending = true;
        isReceiving = true;

        initializeTimerTask();
        timerReceive = new Timer();
        timerReceive.schedule(taskReceive, 0, 1000);
    }

    private void stopTimer() {
        isSending = false;
        isReceiving = false;

        if (timerReceive != null) {
            timerReceive.cancel();
            timerReceive = null;
        }
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.e(getClass().getName(), "onCreate");
        startTimer();
    }

    @Override
    public void onDestroy() {
        Log.e(getClass().getName(), "onDestroy");
        stopTimer();
        super.onDestroy();
    }

    @Override
    public ComponentName startService(Intent service) {
        return super.startService(service);
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }

    public class RouterTransferRateDataBinder extends Binder {
        public RouterTransferRateService getService() {
            return RouterTransferRateService.this;
        }
    }
}