Encode "bytes" with the error correction level "ecLevel". The encoding mode will be chosen
internally by chooseMode(). On success, store the result in "qrCode".
We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
"getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
strong error correction for this purpose.
Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
with which clients can specify the encoding mode. For now, we don't need the functionality.