The available masking rules. Learn more here: https://cloud.google.com/bigquery/docs/column-data-masking-intro#masking_options. Possible values are: SHA256, ALWAYS_NULL, DEFAULT_MASKING_VALUE, LAST_FOUR_CHARACTERS, FIRST_FOUR_CHARACTERS, EMAIL_MASK, DATE_YEAR_MASK.
The name of the BigQuery routine that contains the custom masking routine, in the format of projects/{projectNumber}/datasets/{dataset_id}/routines/{routine_id}.