req.start()
    return completableFuture
  }

  @Test
  fun urlConnection() {
    val conn = engine.openConnection(URL("https://google.com/robots.txt")) as HttpURLConnection

    val text =
      conn.inputStream.use {
        it.bufferedReader().readText()
      }

    assertEquals(200, conn.responseCode)

    assertTrue(text.contains("Disallow"))
  }

 * They don't specify whether a specific proxy server should be used or how to authenticate with that proxy server.

    path: String,
    responseCode: AtomicInteger,
  ): Thread {
    return Thread {
      val url = mockWebServer.url(path).toUrl()
      val conn: HttpURLConnection
      try {
        conn = url.openConnection() as HttpURLConnection
        responseCode.set(conn.responseCode) // Force the connection to hit the "server".
      } catch (ignored: IOException) {
      }
    }
  }