public Node withFirmwareVerifiedAt(Instant instant) {
        var newStatus = status.withFirmwareVerifiedAt(instant);
        var newHistory = history.with(new History.Event(History.Event.Type.firmwareVerified, Agent.system, instant));
        return this.with(newStatus).with(newHistory);
    }
Returns a copy of this node with firmware verified at the given instant
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java