code: func (b *IOPinDriver) WritePinData(pin string, data byte) (err error) {
  	i, err := strconv.Atoi(pin)
  	if err != nil {
  		return
  	}
  
  	buf := []byte{byte(i), data}
  	err = b.adaptor().WriteCharacteristic(pinDataCharacteristic, buf)
  	return err
  }
docs: // WritePinData writes the pin data for a single pin