code: func (c *Client) notifyReceivedInternal(addresses []string) FutureNotifyReceivedResult {
  	// Not supported in HTTP POST mode.
  	if c.config.HTTPPostMode {
  		return newFutureError(ErrWebsocketsRequired)
  	}
  
  	// Ignore the notification if the client is not interested in
  	// notifications.
  	if c.ntfnHandlers == nil {
  		return newNilFutureResult()
  	}
  
  	// Convert addresses to strings.
  	cmd := btcjson.NewNotifyReceivedCmd(addresses)
  	return c.sendCmd(cmd)
  }
docs: // notifyReceivedInternal is the same as notifyReceivedAsync except it accepts
  // the converted addresses as a parameter so the client can more efficiently
  // recreate the previous notification state on reconnect.