@Override
  protected void cacheLoaderChanged(CacheLoader oldLoader) {
    super.cacheLoaderChanged(oldLoader);
    if (oldLoader == null ^ basicGetLoader() == null) {
      new UpdateAttributesProcessor(this).distribute();
    }
  }
invoke a cache writer before a put is performed elsewhere
geode-core/src/main/java/org/apache/geode/internal/cache/DistributedRegion.java