code: func (h *HCI) Accept() (ble.Conn, error) {
  	var tmo <-chan time.Time
  	if h.listenerTmo != time.Duration(0) {
  		tmo = time.After(h.listenerTmo)
  	}
  	select {
  	case <-h.done:
  		return nil, h.err
  	case c := <-h.chSlaveConn:
  		return c, nil
  	case <-tmo:
  		return nil, fmt.Errorf("listner timed out")
  	}
  }
docs: // Accept starts advertising and accepts connection.