@Override
  protected @NotNull ValueReference<K, V> createValueReference(@NotNull RefHashMap.Key<K> key,
                                                               V referent,
                                                               ReferenceQueue<? super V> q) {
    return new WeakValueReference<>(key, referent, q);
  }
@Override
  protected @NotNull ValueReference<K, V> createValueReference(@NotNull RefHashMap.Key<K> key,
                                                               V referent,
                                                               ReferenceQueue<? super V> q)