Pair<Long, Long> getQuotaAndUsage(RestRequest restRequest) {
    long quotaValue = -1L;
    long currentUsage = 0L;
    try {
      Account account = RestUtils.getAccountFromArgs(restRequest.getArgs());
      Container container = RestUtils.getContainerFromArgs(restRequest.getArgs());
      QuotaResource quotaResource =
          account.getQuotaResourceType() == QuotaResourceType.ACCOUNT ? QuotaResource.fromAccount(account)
              : QuotaResource.fromContainer(container);
      quotaValue = getQuotaValueForResource(quotaResource);
      if (quotaValue != -1L) {
        currentUsage = storageUsages.getOrDefault(quotaResource, 0L);
      }
    } catch (Exception e) {
      logger.error("Failed to getQuotaAndUsage for RestRequest {}", restRequest, e);
    }
    return new Pair<>(quotaValue, currentUsage);
  }
Return quota and current usage for the account/container carried in the given {@code restRequest}.
If there is no account and container found in the {@code restRequest}, this method would return -1
for quota. If there is no quota found for the account/container, this method would return -1 for
quota as well.
@param restRequest the {@link RestRequest} that carries account and container in the header.
@return A {@link Pair} whose first element is quota the second element is current storage usage.
ambry-quota/src/main/java/com/github/ambry/quota/storage/StorageQuotaEnforcer.java