code: func (c *Client) ImportPrivKeyRescanAsync(privKeyWIF *btcutil.WIF, label string, rescan bool) FutureImportPrivKeyResult {
  	wif := ""
  	if privKeyWIF != nil {
  		wif = privKeyWIF.String()
  	}
  
  	cmd := btcjson.NewImportPrivKeyCmd(wif, &label, &rescan)
  	return c.sendCmd(cmd)
  }
docs: // ImportPrivKeyRescanAsync returns an instance of a type that can be used to get the
  // result of the RPC at some future time by invoking the Receive function on the
  // returned instance.
  //
  // See ImportPrivKey for the blocking version and more details.