private void checkShutdown() {
    checkReadiness();
    cache.getCancelCriterion().checkCancelInProgress(null);
  }
Check for region closure, region destruction, cache closure as well as distributed system
disconnect. As of 6/21/2007, there were at least four volatile variables reads and one
synchonrization performed upon completion of this method.
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegion.java