Как исправить ошибку Unable to cast object of type

При работе с библиотекой YoutubeExplode(https://github.com/Tyrrrz/YoutubeExplode) возникла такая ошибка:

System.InvalidCastException: 
"Unable to cast object of type '<OfTypeIterator>d__61`1[YoutubeExplode.Videos.Streams.AudioOnlyStreamInfo]' 
to type 'YoutubeExplode.Videos.Streams.AudioOnlyStreamInfo'."

Как я могу ее исправить? Вот код:

using YoutubeExplode;
using IStreamInfo = YoutubeExplode.Videos.Streams.AudioOnlyStreamInfo;

        private async void btnDownload_Click(object sender, RoutedEventArgs e)
        {
            var youtube = new YoutubeClient();

            var streamManifest = await youtube.Videos.Streams.GetManifestAsync("bnsUkE8i0tU");
            var streamInfo = streamManifest.GetAudioOnly();

            if (streamInfo != null)
            {
                var stream = await youtube.Videos.Streams.GetAsync((IStreamInfo)streamInfo);

                await youtube.Videos.Streams.DownloadAsync((IStreamInfo)streamInfo, Path.Combine(LoadDirectory, $"video.mp3") );
            }
        }