public void cancelAll() {
            Iterator<Map.Entry<String, TimerTask>> iterator = tasks.entrySet().iterator();
            while (iterator.hasNext()) {
                iterator.next().getValue().cancel();
                iterator.remove();
            }
        }
The scheduled timers keyed by their key.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/runtime/CoordinatorRuntime.java