ASP.NET MVC Record incoming request

// Use
var parser = new HttpRequestToTextParser();
var res = parser.Parse(Request);
System.IO.File.AppendAllLines(@"c:\\temp\\log_request.txt",res);

// Implementation
public class HttpRequestToTextParser
{
    public List<string> Parse(HttpRequestBase request)
    {
        var list = new List<string>();

        foreach (var headerKey in request.Headers.AllKeys)
        {
            var values = request.Headers.GetValues(headerKey);

            string keyValue = "";
            if (values != null)
            {
                keyValue = string.Join(",", values);
            }

            list.Add($"{headerKey}:{keyValue}");
        }

        Stream req = request.InputStream;
        req.Seek(0, System.IO.SeekOrigin.Begin);
        string body = new StreamReader(req).ReadToEnd();

        list.Add("Body:");
        list.Add(body);

        return list;
    }
}