public void ExtensionPattern_02()
        {
            PatternFactory.AddExtensionPattern(
                "foo",
                str =>
            {
                Assert.Equal("howdy-world:foo", str);
                return(new ExtPattern(str));
            });
            var pattern = PatternFactory.Create("ext:foo:howdy-world:foo");
            var next    = pattern.Next();

            Assert.Equal(next, new DateTime(2030, 11, 11, 11, 11, 11));
            Assert.Equal("ext:foo:howdy-world:foo", pattern.Value);
        }