private void registerWifiSignalStrengthChangeReceiver() {
    IntentFilter filter = new IntentFilter(WifiManager.RSSI_CHANGED_ACTION);
    context.registerReceiver(wifiSignalStrengthChangeReceiver, filter);
  }
Unregisters NetworkEvents.
It should be executed in onDestroy() method in activity
or during destroying instance of class extending Application.
network-events-library/src/main/java/com/github/pwittchen/networkevents/library/NetworkEvents.java