public static <C> AsyncBuilder<C> builder() {
    return new AsyncBuilder<>();
  }
@Test
  void throwsFeignExceptionWithoutBody() {
    server.enqueue(new MockResponse().setBody("success!"));

    TestInterfaceAsync api = AsyncFeign.builder().decoder((response, type) -> {
      throw new IOException("timeout");
    })
        .target(TestInterfaceAsync.class, "http://localhost:" + server.getPort());

    try {
      api.noContent();
    } catch (FeignException e) {
      assertThat(e.getMessage())
          .isEqualTo("timeout reading POST http://localhost:" + server.getPort() + "/");
      assertThat(e.contentUTF8()).isEqualTo("");
    }
  }