@Test
  void singleInterceptor() throws Exception {
    server.enqueue(new MockResponse().setBody("foo"));

    final TestInterfaceAsync api =
        new TestInterfaceAsyncBuilder()
            .requestInterceptor(new ForwardedForInterceptor())
            .target("http://localhost:" + server.getPort());

    final CompletableFuture<?> cf = api.post();

    assertThat(server.takeRequest())
        .hasHeaders(entry("X-Forwarded-For", Collections.singletonList("origin.host.com")));

    checkCFCompletedSoon(cf);
  }
The type of a parameter value may not be the desired type to encode as. Prefer the interface
type.
hc5/src/test/java/feign/hc5/AsyncApacheHttp5ClientTest.java