@After
  public void teardown() {
    if (nettyClient != null) {
      nettyClient.close();
    }
    if (ambryRestServer != null) {
      ambryRestServer.shutdown();
    }
  }
Shuts down the Ambry frontend server.
ambry-frontend/src/integration-test/java/com/github/ambry/frontend/FrontendQuotaIntegrationTest.java