void appendControlEventWithDeadline(String name, Runnable handler, long deadlineNs) {
        ControllerEvent event = new ControllerEvent(name, handler);
        queue.appendWithDeadline(deadlineNs, event);
    }
A controller event for handling internal state changes, such as Raft inputs.
metadata/src/main/java/org/apache/kafka/controller/QuorumController.java