@Override
    public RuntimeException generateCancelledException(Throwable t) {
      String reason = cancelInProgress();
      if (reason == null) {
        return null;
      }
      return new PoolCancelledException(reason, t);
    }
A cancel criterion that checks only if this pool has been closed. This is necessary because
there are some things that we want to allow even after the cache has started closing.
geode-core/src/main/java/org/apache/geode/cache/client/internal/PoolImpl.java