default List<VirtualColumn> acidVirtualColumns() {
    return Collections.emptyList();
  }
Specifies which additional virtual columns should be added to the virtual column registry during compilation
for tables that support ACID operations.

Should only return a non-empty list if
{@link HiveStorageHandler#supportsAcidOperations()} returns something
other NONE.

@return the list of ACID virtual columns
ql/src/java/org/apache/hadoop/hive/ql/metadata/HiveStorageHandler.java