code: func (h *HCI) Send(c Command, r CommandRP) error {
  	b, err := h.send(c)
  	if err != nil {
  		return err
  	}
  	if len(b) > 0 && b[0] != 0x00 {
  		return ErrCommand(b[0])
  	}
  	if r != nil {
  		return r.Unmarshal(b)
  	}
  	return nil
  }
docs: // Send ...