docs: @RequiresPermission(Manifest.permission.ACCESS_NETWORK_STATE)
    public static Observable<Connectivity> observeNetworkConnectivity(final Context context) {
      final NetworkObservingStrategy strategy;
  
      if (Preconditions.isAtLeastAndroidMarshmallow()) {
        strategy = new MarshmallowNetworkObservingStrategy();
      } else if (Preconditions.isAtLeastAndroidLollipop()) {
        strategy = new LollipopNetworkObservingStrategy();
      } else {
        strategy = new PreLollipopNetworkObservingStrategy();
      }
  
      return observeNetworkConnectivity(context, strategy);
    }