private void cacheWriteBeforeRegionClear(RegionEventImpl event)
      throws CacheWriterException, TimeoutException {
    // copy into local var to prevent race condition
    CacheWriter writer = basicGetWriter();
    if (writer != null) {
      final long start = getCachePerfStats().startCacheWriterCall();
      try {
        writer.beforeRegionClear(event);
      } finally {
        getCachePerfStats().endCacheWriterCall(start);
      }
    }
    serverRegionClear(event);
  }
@return true if cacheWrite was performed
@see DistributedRegion#cacheWriteBeforeRegionDestroy(RegionEventImpl)
geode-core/src/main/java/org/apache/geode/internal/cache/LocalRegion.java