int downloadId = FlutterAndroidDownloader.download("url", "path", "fileName","originName","headers");

FlutterAndroidDownloader.listen((id) {
  print("success $id");
  // to do something
});

FlutterAndroidDownloader.listen((id) {
  print("success $id");
});

void download() async {
    int id = await FlutterAndroidDownloader.download(
        "https://qd.myapp.com/myapp/qqteam/AndroidQQ/mobileqq_android.apk",
        "/ABC",
        "qq.apk",
        "QQ",
        {}
    );
    print("ID => $id");
}