@Override
  public Quota getQuota(QuotaResource quotaResource, QuotaName quotaName) throws QuotaException {
    checkSupported(quotaName, quotaResource);

    final String resourceId = quotaResource.getResourceId();
    assertResourceId(resourceId, false);
    return new Quota<>(quotaName, cuQuota.get(resourceId).getQuotaValue(quotaName), quotaResource);
  }
Constructor for {@link AmbryCUQuotaSource}.
@param quotaConfig {@link QuotaConfig} object.
@param accountService {@link AccountService} object.
@param quotaMetrics {@link QuotaMetrics} object.
@param routerConfig {@link RouterConfig} object.
@throws IOException in case of any exception.
ambry-quota/src/main/java/com/github/ambry/quota/capacityunit/AmbryCUQuotaSource.java