How can I use showDialog with await

Question

I have three examples of showDialog. I presume that _showAlert1 is correct, however it uses 2 functions to achieve it. _showAlert2 also works, however I presume it is not correct because I believe that showDialog is async, and I presume that this function relies on the dialog being displayed in sufficient time. _showAlert3 does not work because the dialog stays on the screen and does not clear.

If _showAlert2 although it works is incorrect for the above reason, could someone please show me how this should be structured so that this can be done in one function.

Examples:

void _showAlert0(BuildContext context, String text, int seconds) async {
    return await showDialog(
        barrierDismissible: false,
        context: context,
        builder: (context) => AlertDialog(
              title: Text("Error"),
              content: Text(text),
            ));
  }

  void _showAlert1(BuildContext context, String text, int seconds) async {
    _showAlert0(context, text, seconds);
    await Future.delayed(Duration(seconds: seconds));
    Navigator.of(context).pop(true);
  }

  void _showAlert2(BuildContext context, String text, int seconds) async {
    showDialog(
        barrierDismissible: false,
        context: context,
        builder: (context) => AlertDialog(
              title: Text("Error"),
              content: Text(text),
            ));
    await Future.delayed(Duration(seconds: seconds));
    Navigator.of(context).pop(true);
  }

void _showAlert3(BuildContext context, String text, int seconds) async {
    await showDialog(
        barrierDismissible: false,
        context: context,
        builder: (context) => AlertDialog(
              title: Text("Error"),
              content: Text(text),
            ));
    await Future.delayed(Duration(seconds: seconds));
    Navigator.of(context).pop(true);
}

Answer 1

Not sure if there is a better way, but the following appears to work. Note the "then" clause on the call to showDialog().

void _showAlert3(BuildContext context, String text, int seconds) async {
    showDialog(
        barrierDismissible: false,
        context: context,
        builder: (context) => AlertDialog(
              title: Text("Error"),
              content: Text(text),
            )).then((val) {});
    await Future.delayed(Duration(seconds: seconds));
    Navigator.of(context).pop(true);
  }

As for trolls, RTFQ ("structured so that this can be done in one function") and if you don't want to help then go away.