Strength keyStrength() {
    return entryHelper.keyStrength();
  }

  @VisibleForTesting
  Strength valueStrength() {
    return entryHelper.valueStrength();
  }

  @VisibleForTesting
  Equivalence<Object> valueEquivalence() {
    return entryHelper.valueStrength().defaultEquivalence();
  }

  // ConcurrentMap methods

  @Override
  public boolean isEmpty() {
    /*