@Override
  public QuotaEnforcer getQuotaEnforcer() {
    return ambryCUQuotaEnforcer;
  }
Constructor for {@link AmbryCUQuotaEnforcerFactory}.
@param quotaConfig {@link QuotaConfig} object.
@param quotaSource {@link QuotaSource} object.
@param accountStatsStore the {@link AccountStatsStore}.
ambry-quota/src/main/java/com/github/ambry/quota/capacityunit/AmbryCUQuotaEnforcerFactory.java