.url(server.url("/"))
          .post(AsyncRequestBody())
          .build(),
      )
    call.execute().use { response ->
      val requestBody = (call.request().body as AsyncRequestBody?)!!.takeSink()
      requestBody.writeUtf8("request A\n")
      requestBody.flush()
      val responseBody = response.body.source()
      assertThat(responseBody.readUtf8Line())
        .isEqualTo("response B")