protected boolean isCacheClosing() {
    return getLocalRegion().getCache().isClosed();
  }
An ExpiryTask is sent run() to perform its task. Note that this run() method should never throw
an exception - otherwise, it takes out the java.util.Timer thread, causing an exception
whenever we try to schedule more expiration tasks.
geode-core/src/main/java/org/apache/geode/internal/cache/ExpiryTask.java