UrlToFile.cs

public static TextFieldParser GetTextFieldParser(string source)
{
    if (!source.IsUrl())
        return new TextFieldParser(source);

    var file = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), "files", $"{DateTime.Now:yyyyMMddHHmmssfff}", Path.GetFileName(source));
    var path = Path.GetDirectoryName(file);
    if (!Directory.Exists(path))
        Directory.CreateDirectory(path);

    // Save to file before calling the parser
    using (var response = _httpClient.GetAsync(source).GetAwaiter().GetResult())
    {
        response.EnsureSuccessStatusCode();

        using (var stream = response.Content.ReadAsStreamAsync().GetAwaiter().GetResult())
        using (var fileStream = File.Create(file))
        {
            stream.Seek(0, SeekOrigin.Begin);
            stream.CopyTo(fileStream);
        }

        return new TextFieldParser(file);
    }
}