code: func (c *Conn) NewSyncConn() *SyncConn {
  	return &SyncConn{
  		SyncScanner: c.Scanner.NewSyncScanner(),
  		SyncSender:  c.Sender.NewSyncSender(),
  	}
  }
docs: // NewSyncConn returns connection that can operate in sync mode.
  // The connection must already have been switched (by sending the sync command
  // to a specific device), or the return connection will return an error.