private final transient ConcurrentMap<E, AtomicInteger> countMap;

  // This constant allows the deserialization code to set a final field. This holder class
  // makes sure it is not initialized unless an instance is deserialized.
  private static class FieldSettersHolder {
    static final FieldSetter<? super ConcurrentHashMultiset<?>> COUNT_MAP_FIELD_SETTER =
        Serialization.getFieldSetter(ConcurrentHashMultiset.class, "countMap");
  }

  private final transient ConcurrentMap<E, AtomicInteger> countMap;

  // This constant allows the deserialization code to set a final field. This holder class
  // makes sure it is not initialized unless an instance is deserialized.
  private static class FieldSettersHolder {
    static final FieldSetter<? super ConcurrentHashMultiset<?>> COUNT_MAP_FIELD_SETTER =
        Serialization.getFieldSetter(ConcurrentHashMultiset.class, "countMap");
  }