src/vs/workbench/common/notifications.ts/NotificationViewItem/constructor
class NotificationViewItem:	private constructor(
		readonly id: string | undefined,
		private _severity: Severity,
		private _sticky: boolean | undefined,
		private _silent: boolean | undefined,
		private _message: INotificationMessage,
		private _source: string | { label: string; id: string } | undefined,
		progress: INotificationProgressProperties | undefined,
		actions?: INotificationActions
	) {
		super();

		if (progress) {
			this.setProgress(progress);
		}

		this.setActions(actions);
	}