(secondaryPreferred: StringAdd).self
(secondaryPreferred: StringFormat).self
(secondaryPreferred: ArrowAssoc[SecondaryPreferred]).x
(Since version 2.10.0) Use leftOfArrow instead
(secondaryPreferred: Ensuring[SecondaryPreferred]).x
(Since version 2.10.0) Use resultOfEnsuring instead
Read from any secondary, or from the primary if they are not available.