public NotificationEntity setModifiedOn(OffsetDateTime modifiedOn) {
        this.modifiedOn = modifiedOn;
        return this;
    }
Models a notification, which can also contain a payload.

@author Marc Savy {@literal <marc@blackparrotlabs.io>}
manager/api/beans/src/main/java/io/apiman/manager/api/beans/notifications/NotificationEntity.java