Function of_event 

pub(crate) fn of_event(key: &str, start: i64) -> String

An event’s reminder before it, as its details say it (AgendaPage.qml), the occurrence starting at start: {line, remind, writable}: “Reminder: 13:15” (with its day when another), or “No reminder before it”; its own choice; whether it can be changed here. “” when the event is not found.