// ConnectivityManager.java

/**
     * Registers to receive notifications about all networks which satisfy the given
     * {@link NetworkRequest}.  The callbacks will continue to be called until
     * either the application exits or {@link #unregisterNetworkCallback(NetworkCallback)} is
     * called.
     *
     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
     * number of outstanding requests to 100 per app (identified by their UID), shared with
     * all variants of this method, of {@link #requestNetwork} as well as
     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
     * Requesting a network with this method will count toward this limit. If this limit is
     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
     * make sure to unregister the callbacks with
     * {@link #unregisterNetworkCallback(NetworkCallback)}.
     *
     * @param request {@link NetworkRequest} describing this request.
     * @param networkCallback The {@link NetworkCallback} that the system will call as suitable
     *                        networks change state.
     *                        The callback is invoked on the default internal Handler.
     * @throws RuntimeException if the app already has too many callbacks registered.
     */
    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
    public void registerNetworkCallback(@NonNull NetworkRequest request,
            @NonNull NetworkCallback networkCallback) {
        registerNetworkCallback(request, networkCallback, getDefaultHandler());
    }