docs: @RequiresPermission(Manifest.permission.ACCESS_NETWORK_STATE)
    public static Observable<Connectivity> observeNetworkConnectivity(final Context context,
        final NetworkObservingStrategy strategy) {
      Preconditions.checkNotNull(context, "context == null");
      Preconditions.checkNotNull(strategy, "strategy == null");
      return strategy.observeNetworkConnectivity(context);
    }