code: func (b *Bitmap) Info() bitmapInfo {
  	info := bitmapInfo{
  		OpN:        b.opN,
  		Containers: make([]containerInfo, 0, b.Containers.Size()),
  	}
  
  	citer, _ := b.Containers.Iterator(0)
  	for citer.Next() {
  		k, c := citer.Value()
  		ci := c.info()
  		ci.Key = k
  		info.Containers = append(info.Containers, ci)
  	}
  	return info
  }
docs: // Info returns stats for the bitmap.