(primaryPrefered: StringAdd).self
(primaryPrefered: StringFormat).self
(primaryPrefered: ArrowAssoc[PrimaryPrefered]).x
(Since version 2.10.0) Use leftOfArrow
instead
(primaryPrefered: Ensuring[PrimaryPrefered]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
Read from the primary if it is available, or secondaries if it is not.