public void WithCredentials_WhenSet_ExpectSettingsUpdated()
        {
            // arrange
            var          expected = new NetworkCredential("username", "password");
            var          builder  = CreateHttpClientBuilder();
            ICredentials actual   = null;
            // act
            var client = builder.WithCredentials(expected).WithConfiguration(s =>
            {
                actual = s.Credentials;
            }).Build();

            // assert
            actual.ShouldNotBeNull();
            actual.ShouldBe(expected);
        }