Thread.sleep(500)
    server.send("Hello, WebSockets!")
    clientListener.assertTextMessage("Hello, WebSockets!")
    closeWebSockets(webSocket, server)
  }

  /**
   * We had a bug where web socket connections were leaked if the HTTP connection upgrade was not
   * successful. This test confirms that connections are released back to the connection pool!
   * https://github.com/square/okhttp/issues/4258