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