Is it possible to sign a lib event on a REST request and wait for the return?

Question

I wonder if it is possible to sign an event from a third party lib, which in the case is Microsoft.Speech.dll. Because, in my attempt, it did not work very well, ie, recognition does not happen and the event is not fired. I tried using Task and also without, but I did not succeed. I don’t really know if it is possible. sign an event in this way and the request wait. Thanks in advance for the attention and possible help. Follow the code.

    private string retorno = string.Empty;

    public async Task<string> Get()
    {
        var result = Task.Run(() =>
        {
            var comandos = new string[] { "comando 1", "comando 2", "comando N" };
            var ci = new CultureInfo("pt-BR");
            var sre = new SpeechRecognitionEngine(ci);
            var gramatica = new Choices();
            gramatica.Add(comandos);
            var gb = new GrammarBuilder(gramatica);
            var g = new Grammar(gb);
            sre.RequestRecognizerUpdate();
            sre.LoadGrammarAsync(g);
            sre.SpeechRecognized += Sre_SpeechRecognized;

            sre.SetInputToWaveFile("anyWavfile.wav");
            sre.RecognizeAsync(RecognizeMode.Multiple);

        });

        await Task.WhenAll(result);

        return retorno;
    }

    private void Sre_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
    {
        retorno += e.Result.Text;
    }

Answer 1

Follow the solution I applied

private string text = string.Empty;
private ManualResetEvent manualResetEvent = new ManualResetEvent(false);

public string Get()
{
    var result = Task.Run(() =>
    {
        //code...

    });

    manualResetEvent.WaitOne();   

    return text;
}

private void Sre_RecognizeCompleted(object sender, RecognizeCompletedEventArgs e)
{
    manualResetEvent.Set();
}

private void Sre_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
{
    text += e.Result.Text;
}