Асинхронный вызов httpWebResponse

GetYoulaAdvert(url);

 public class YoulaWebWorker
    {
        string youlaStringAdverts = "";
        public string YoulaGetAdverts (string url)
        {
            GetYoulaAdvert(url);
            return youlaStringAdverts = "";
 
        }
       async Task GetYoulaAdvert(string url)
        {
            HttpWebRequest youlaRequest = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse youlaResponse = (HttpWebResponse)await youlaRequest.GetResponseAsync();
            using (Stream youlaStream = youlaResponse.GetResponseStream())
            {
                using (StreamReader youlaAdvertsStreamReader = new StreamReader(youlaStream))
                {
                    youlaStringAdverts = await youlaAdvertsStreamReader.ReadToEndAsync();
                }
            }
            youlaResponse.Close();
            
        }
    }

public class YoulaWebWorker
{
    public async Task<string> GetYoulaAdvert(string url)
    {
        HttpWebRequest youlaRequest = (HttpWebRequest)WebRequest.Create(url);
        using (HttpWebResponse youlaResponse = (HttpWebResponse)await youlaRequest.GetResponseAsync())
        using (Stream youlaStream = youlaResponse.GetResponseStream())
        using (StreamReader youlaAdvertsStreamReader = new StreamReader(youlaStream))
        {
            return await youlaAdvertsStreamReader.ReadToEndAsync();
        }
    }
}

string advert = await GetYoulaAdvert(url);