The identifier to login with, under either of its names. Exactly one is required: identifier,
which pairs with identifierType, or username, its original spelling, which remains accepted so
existing callers keep working. Supplying both is not an error — identifier wins.
Remarks
Shared by the login and login-id screens, whose LoginOptions each intersect it with their own
remaining fields.
The identifier to login with, under either of its names. Exactly one is required:
identifier, which pairs withidentifierType, orusername, its original spelling, which remains accepted so existing callers keep working. Supplying both is not an error —identifierwins.