long sum = 0;
    for (Segment<K, V> segment : segments) {
      sum += segment.count;
    }
    return sum;
  }

  @Override
  public int size() {
    return Ints.saturatedCast(longSize());
  }

  @CanIgnoreReturnValue // TODO(b/27479612): consider removing this
  @Override
  @CheckForNull
  public V get(@CheckForNull Object key) {
    if (key == null) {