public void Should_Happen_During()
        {
            var d = new DateTimeOffsetRange(Now, OneDayAfterNow);

            d.HappenedDuring(Now.AddHours(1)).Should().BeTrue();
            d.HappenedDuring(Now).Should().BeTrue();            // date at begin of range is included
            d.HappenedDuring(OneDayAfterNow).Should().BeTrue(); // date at end of range is included
        }
 /// <summary>
 ///     Evaluates if the datetime instance, did happen during the given period.
 /// </summary>
 public static bool HappenedDuring(this DateTimeOffset @this, DateTimeOffsetRange period)
 {
     if (period == null)
     {
         throw new ArgumentNullException(nameof(period));
     }
     return(period.HappenedDuring(@this));
 }