public Set<VersionSource> clearEntries(RegionVersionVector rvv) {
    return entries.clear(rvv, null);
  }
Removes entries and recursively destroys subregions.

@param eventSet collects the events for all destroyed regions if null, then we're closing so
       don't send events to callbacks or destroy the disk region
geode-core/src/main/java/org/apache/geode/internal/cache/LocalRegion.java