@Override
  public SecurityService getSecurityService() {
    return new AmbrySecurityService(frontendConfig, frontendMetrics, urlSigningService,
        new HostLevelThrottler(hostThrottleConfig), quotaManager);
  }
Default implementation of {@link SecurityServiceFactory} for Ambry
<p/>
Returns a new instance of {@link AmbrySecurityService} on {@link #getSecurityService()} call.
ambry-frontend/src/main/java/com/github/ambry/frontend/AmbrySecurityServiceFactory.java