@Test
  void customExpander() throws Exception {
    server.enqueue(new MockResponse());

    TestInterface api = new TestInterfaceBuilder().target("http://localhost:" + server.getPort());

    api.expand(new TestClock(1234L));

    assertThat(server.takeRequest()).hasPath("/?clock=1234");
  }
The type of a parameter value may not be the desired type to encode as. Prefer the interface
type.
core/src/test/java/feign/FeignUnderAsyncTest.java