code: func (f *FIFO) List() []interface{} {
  	f.lock.RLock()
  	defer f.lock.RUnlock()
  	list := make([]interface{}, 0, len(f.items))
  	for _, item := range f.items {
  		list = append(list, item)
  	}
  	return list
  }
docs: // List returns a list of all the items.