public String build() {
        return build(null, Maps.<String, Object>newHashMap());
    }
@Test
    public void testScheme() {
        UriSpec spec = new UriSpec("{scheme}://foo.com");

        ServiceInstanceBuilder<Void> builder = new ServiceInstanceBuilder<Void>();
        builder.id("x");
        builder.name("foo");
        builder.port(5);
        ServiceInstance<Void> instance = builder.build();
        assertEquals(spec.build(instance), "http://foo.com");

        builder.sslPort(5);
        instance = builder.build();
        assertEquals(spec.build(instance), "https://foo.com");
    }