void deliverNextAbnormalEvent() {
    deliverNextAbnormalEvent = true;
  }
Used by the OffHeapMemoryUsageListener to tell us that the next abnormal event should be
delivered even if the state does not change as long as the memory usage changed. For some
reason, unknown to me, if we stay in an abnormal state for more than a second then we want to
send another event to update the memory usage.
geode-core/src/main/java/org/apache/geode/internal/cache/control/OffHeapMemoryMonitor.java