podcast-agent/Program.cs

namespace podcast_agent
{
    using System.Xml.Linq;

    class Program
    {
        static async Task Main(string[] args)
        {
            var downloader = new HttpClient();
            downloader.DefaultRequestHeaders.UserAgent.ParseAdd("wget-is-not-a-crime");

            var xml = XDocument.Load("https://feeds.npr.org/500005/podcast.xml");

            XNamespace ns = "http://www.itunes.com/dtds/podcast-1.0.dtd";
            foreach (var item in xml.Descendants("item"))
            {
                var title = item.Element("title")?.Value;
                var ext=".wav";
                var attachmentLink = item.Element("enclosure")?.Attribute("url")?.Value.ToString();
                var probableFilename = attachmentLink.Substring(0, attachmentLink.IndexOf('?'));
                if(probableFilename.LastIndexOf('.') > 0)
                {
                    ext = probableFilename.Substring(probableFilename.LastIndexOf('.'));
                }

                Console.WriteLine($"{title}, {attachmentLink}");
                var downloadPath = title + ext;
                var dlResult = (await downloader.GetAsync(attachmentLink));
                File.WriteAllBytes(downloadPath, await dlResult.Content.ReadAsByteArrayAsync());
            }

        }
    }
}