@Override
  public QuotaResource getQuotaResource() throws QuotaException {
    return QuotaResource.fromRestRequest(restRequest);
  }
Constructor for {@link PreProcessQuotaChargeCallback}.
@param quotaManager {@link QuotaManager} object responsible for charging the quota.
@param restRequest {@link RestRequest} for which quota is being charged.
ambry-quota/src/main/java/com/github/ambry/quota/PreProcessQuotaChargeCallback.java