static List<String> getPartiallySealedReplicas(ZNRecord znRecord) {
    List<String> partiallySealedReplicas = znRecord.getListField(ClusterMapUtils.PARTIALLY_SEALED_STR);
    return partiallySealedReplicas == null ? new ArrayList<>() : partiallySealedReplicas;
  }
Get the list of partially sealed replicas on a given instance. This is guaranteed to return a non-null list. It
would return an empty list if there are no partially sealed replicas or if the field itself is absent for this
instance.
@param znRecord the {@link ZNRecord} associated with the interested instance.
@return the list of partially sealed replicas.
ambry-clustermap/src/main/java/com/github/ambry/clustermap/ClusterMapUtils.java