public static AndConstraint <NumericAssertions <double> > BeGreaterOrEqualToMinimumSleepLength(this NullableNumericAssertions <double> duration,
                                                                                                       int numberOfSleeps
                                                                                                       )
        {
            var expectedTransactionLength = numberOfSleeps * WaitHelpers.SleepLength;

            return(duration.NotBeNull()
                   .And.BeGreaterOrEqualTo(expectedTransactionLength, $"we expected {numberOfSleeps} to influence the total duration"));
        }
 BeGreaterOrEqualToMinimumSleepLength(this NullableNumericAssertions <double> duration) =>
 duration.NotBeNull().And.BeGreaterOrEqualTo(WaitHelpers.SleepLength);