public void ProcessAsync_WhenTestList1_ExpectLoggingAndTimingOutput()
        {
            // arrange
            var mockConfiguration = new Mock<IConfiguration<KeyAuthentication>>();

            mockConfiguration.Setup(r => r.Get).Returns(() => new KeyAuthentication { LicenseKey = MyLicenseKey });

            var defaultClient = new DefaultClient(mockConfiguration.Object);

            var defaultService = new DefaultService(defaultClient);
            defaultService.ProgressChanged += (o, args) => Console.WriteLine(JsonConvert.SerializeObject(args));

            // act
            var stopwatch = Stopwatch.StartNew();
            var verificationResponses = defaultService.ProcessAsync(new VerificationRequest { Emails = TestList1 }, CancellationToken.None).Result;
            stopwatch.Stop();

            // assert
            Console.WriteLine("# emails checked: {0}", verificationResponses.Results.Count);
            Console.WriteLine(JsonConvert.SerializeObject(verificationResponses));
            WriteTimeElapsed(stopwatch.ElapsedMilliseconds);
        }