.url(server.url("/"))
        .header("User-Agent", "AsyncApiTest")
        .build()
    client.newCall(request).enqueue(callback)
    callback.await(request.url)
      .assertCode(200)
      .assertHeader("Content-Type", "text/plain")
      .assertBody("abc")
    assertThat(server.takeRequest().headers["User-Agent"]).isEqualTo("AsyncApiTest")
  }

  @Test