public async Task Returns1ForTwoCallsInTwoSeconds()
            {
                var target = new ClientStatistic();

                target.IncreaseRequestCount();
                await Task.Delay(1100);

                target.IncreaseRequestCount();
                Assert.AreEqual(1, target.RequestsPerSecond);
            }
            public void Returns1ForFirstCall()
            {
                var target = new ClientStatistic();

                target.IncreaseRequestCount();
                Assert.AreEqual(1, target.RequestsPerSecond);
            }