I'm integrating with polkadot-vault, which uses a QR code to air-gap sign transactions.

Their protocol requires raw binary encoding - Uint8Array goes in, gets read byte-by-byte and appended. However, this library only accepts strings, and even if I create a string from that binary, currently mode: 'byte' uses new TextEncoder() which encodes each byte using UTF-8, which breaks the payload.

Would it be acceptable to add an option to provide a specific encoder/decoder?

Maybe another option would be to add a separate set of functions to encode/decode "byte" QR codes using Uint8Arrays as inputs and outputs.