@Override
  public Object setValue(Object value) {
    return region.put(getKey(), value);
  }
Returns the entry's RegionEntry if it "checks" out. The check is to see if the region entry
still exists.

@throws EntryNotFoundException if the RegionEntry has been removed.
geode-core/src/main/java/org/apache/geode/internal/cache/ExpiryRegionEntry.java