Optionaloptions: { defaultKey?: string; functionMap?: Record<string, string> }OptionaldefaultKey?: stringThe Fluent identifier or numeric literal to use for the
default/fallback variant, which is labelled as * in MessageFormat 2,
when not explicitly defined in the data.
Defaults to other.
OptionalfunctionMap?: Record<string, string>A mapping of custom MessageFormat 2 → Fluent function names.
Convert a Model.Message data object into a Fluent.Pattern (i.e. the value of a Fluent message or an attribute).