code: func (c *Cache) GetBytes(id string) (ItemInfo, []byte, error) {
  	id = cleanID(id)
  
  	c.nlocker.Lock(id)
  	defer c.nlocker.Unlock(id)
  
  	info := ItemInfo{Name: id}
  
  	if r := c.getOrRemove(id); r != nil {
  		defer r.Close()
  		b, err := ioutil.ReadAll(r)
  		return info, b, err
  	}
  
  	return info, nil, nil
  }
docs: // GetBytes gets the file content with the given id from the cahce, nil if none found.