public void ParseISO8601StringTest()
        {
            Assert.AreEqual(null, IETFValueEncoding.ParseISO8601String("asdfflkjasdf"));
            DateTime now = DateTime.Now;

            foreach (var f in IETFValueEncoding.ISO8601DT_FORMATS)
            {
                string s = now.ToString(f);
                Assert.IsTrue(IETFValueEncoding.ParseISO8601String(s).HasValue);
            }
        }