@SuppressWarnings("unchecked")
      WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> newValueReference =
          (WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>>) valueReference;
      WeakValueReference<K, V, StrongKeyWeakValueEntry<K, V>> previous = entry.valueReference;
      entry.valueReference = newValueReference;
      previous.clear();
    }

    @Override
    void maybeDrainReferenceQueues() {