protected void cacheLoaderChanged(final CacheLoader newLoader, final CacheLoader oldLoader) {
    StoppableWriteLock lock = bucketCreationLock.writeLock();
    lock.lock();
    try {
      loader = newLoader;
      visitBuckets((bucketId, r) -> {
        AttributesMutator mut = r.getAttributesMutator();
        if (logger.isDebugEnabled()) {
          logger.debug("setting new cache loader in bucket region: {}", newLoader);
        }
        mut.setCacheLoader(newLoader);
      });
    } finally {
      lock.unlock();
    }
  }
sent by the partitioned region when its loader has changed
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegionDataStore.java