public void WithCredentials_throws_argumentException_for_invalid_args()
        {
            var config = new ClusterOptions();

            Assert.Throws <ArgumentException>(() => config.WithCredentials(null, null));
            Assert.Throws <ArgumentException>(() => config.WithCredentials(string.Empty, null));
            Assert.Throws <ArgumentException>(() => config.WithCredentials(null, string.Empty));
            Assert.Throws <ArgumentException>(() => config.WithCredentials(string.Empty, string.Empty));
        }