code: func (r FutureDumpPrivKeyResult) Receive() (*btcutil.WIF, error) {
  	res, err := receiveFuture(r)
  	if err != nil {
  		return nil, err
  	}
  
  	// Unmarshal result as a string.
  	var privKeyWIF string
  	err = json.Unmarshal(res, &privKeyWIF)
  	if err != nil {
  		return nil, err
  	}
  
  	return btcutil.DecodeWIF(privKeyWIF)
  }
docs: // Receive waits for the response promised by the future and returns the private
  // key corresponding to the passed address encoded in the wallet import format
  // (WIF)