@Override
  public void putAll(Map m) {
    if (m != null) {
      for (Object i : m.entrySet()) {
        Map.Entry me = (Map.Entry) i;
        put(me.getKey(), me.getValue());
      }
    }
  }
Only called by internal code to bypass exportValue() method

@return internal map
geode-core/src/main/java/org/apache/geode/cache/operations/internal/UpdateOnlyMap.java