public void CloseTo()
        {
            // Sometimes it's handy to have some leniancy on DateTimes in tests
            // Particularly if you've got something that hits the database!

            var firstDate  = new DateTime(2018, 03, 07, 19, 00, 00);
            var secondDate = new DateTime(2018, 03, 07, 19, 30, 25);

            secondDate.Should().BeCloseTo(firstDate, 30.Minutes());

            // Okay so 30 minutes might be an extreme example, but you could do ms too!

            var thirdDate = new DateTime(2018, 03, 07, 19, 00, 00).AddMilliseconds(4);

            firstDate.Should().BeCloseTo(firstDate, FILL_ME_IN.Milliseconds()); // Change FILL_ME_IN to make this pass
        }