@Override
  public Set entrySet() {
    if (entrySet == null) {
      entrySet = Collections.unmodifiableSet(new EntrySet());
    }
    return entrySet;
  }
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