@Override
  public QuotaEnforcer getQuotaEnforcer() {
    return quotaEnforcer;
  }
Constructor to instantiate a factory.
@param quotaConfig the {@link QuotaConfig}.
@param quotaSource the {@link QuotaSource}.
@param accountStatsStore the {@link AccountStatsStore}.
@param quotaMetrics The {@link QuotaMetrics}.
@throws Exception
ambry-quota/src/main/java/com/github/ambry/quota/storage/StorageQuotaEnforcerFactory.java