@Override
  public CustomExpiry setCustomEntryIdleTimeout(CustomExpiry custom) {
    checkReadiness();
    if (custom != null && !statisticsEnabled) {
      throw new IllegalStateException(
          "Cannot set idle timeout when statistics are disabled.");
    }

    CustomExpiry old = getCustomEntryIdleTimeout();
    customEntryIdleTimeout = custom;
    updateEntryExpiryPossible();
    idleTimeoutChanged(getEntryIdleTimeout());
    return old;
  }
Initialize any wrapped RegionMembershipListeners in the cache listener list
geode-core/src/main/java/org/apache/geode/internal/cache/AbstractRegion.java