code: func ReleaseLock(ctx context.Context, backend Backend, lockName string) error {
  	if lockName == "" {
  		return trace.BadParameter("missing parameter lockName")
  	}
  	key := []byte(filepath.Join(locksPrefix, lockName))
  	if err := backend.Delete(ctx, key); err != nil {
  		return trace.Wrap(err)
  	}
  	return nil
  }
docs: // ReleaseLock forces lock release