@Override
  public Collection<? extends PartitionId> getAssignedPartitionIds() {
    return Collections.unmodifiableCollection(assignedPartitionIds);
  }
Register {@link DeprecatedContainerCloudSyncTask}s to sync deleted container information from account service to
VCR.

@param engine the {@link StateMachineEngine} to register the task state model.
ambry-cloud/src/main/java/com/github/ambry/cloud/HelixVcrClusterParticipant.java