public boolean areNotificationsEnabled(String channelName) throws RemoteException {
        Bundle args = new NotificationsEnabledArgs(channelName).toBundle();
        return ResultArgs.fromBundle(mService.areNotificationsEnabled(args)).success;
    }
Checks whether notifications are enabled.
@param channelName The name of the channel to check enabled status. Only used on Android O+.
@return Whether notifications or the notification channel is blocked for the client app.
@throws RemoteException If the Service dies while responding to the request.
customtabs/src/android/support/customtabs/trusted/TrustedWebActivityServiceWrapper.java