@Override
  public Future<Void> updateBlobTtl(RestRequest restRequest, String blobId, String serviceId, long expiresAtMs,
      Callback<Void> callback, QuotaChargeCallback quotaChargeCallback) {
    ttlUpdateServiceId = serviceId;
    return completeOperation(null, callback, OpType.UpdateBlobTtl);
  }
Enumerates the different operation types in the router.
ambry-frontend/src/test/java/com/github/ambry/frontend/FrontendRestRequestServiceTest.java