.build();

    Request request = new Request.Builder()
        .url("ws://echo.websocket.org")
        .build();
    client.newWebSocket(request, this);

    // Trigger shutdown of the dispatcher's executor so this process exits immediately.
    client.dispatcher().executorService().shutdown();
  }

  @Override public void onOpen(WebSocket webSocket, Response response) {

    val parentFile = parentFile ?: return false
    if (parentFile == directory) return true
    return parentFile.isDescendentOf(directory)
  }

  /**
   * See FinalizationTester for discussion on how to best trigger GC in tests.
   * https://android.googlesource.com/platform/libcore/+/master/support/src/test/java/libcore/
   * java/lang/ref/FinalizationTester.java
   */
  @Throws(Exception::class)
  @JvmStatic