code: func (mem *Memory) Create(key string, rls *rspb.Release) error {
  	defer unlock(mem.wlock())
  
  	if recs, ok := mem.cache[rls.Name]; ok {
  		if err := recs.Add(newRecord(key, rls)); err != nil {
  			return err
  		}
  		mem.cache[rls.Name] = recs
  		return nil
  	}
  	mem.cache[rls.Name] = records{newRecord(key, rls)}
  	return nil
  }
docs: // Create creates a new release or returns ErrReleaseExists.