OptionalactionsOptional buttons that invoke callbacks when clicked.
OptionalfontFont names referenced by this notification; used by NotificationCenter.removeResolvedFontMissedNotifications to clear entries when those fonts are no longer missing.
Unique identifier assigned automatically when the notification is created.
OptionalmessageOptional longer description body; omitted for title-only toasts.
OptionalpersistentWhen true, the notification is not auto-dismissed and must be closed
manually or via NotificationCenter.remove.
OptionalsourceGroups related notifications for selective removal (e.g. resolved missed-font alerts).
OptionaltimeoutAuto-dismiss delay in milliseconds.
Ignored when persistent is true.
Time the notification was created.
Short headline shown in the notification header.
Visual severity and icon category (info, warning, error, or success).
A single notification entry displayed in the notification center panel.
Notifications are ordered by insertion time (newest first) and may include optional action buttons and auto-dismiss behavior.