Feature request: streaming mode (dynamically append ABC text while playing)

[BlinkDL]

Thanks for the great lib.

I am building an AI music generator (based on https://huggingface.co/BlinkDL/rwkv-5-music) which can dynamically generate ABC text.

It will be cool if we can dynamically append ABC text while playing.

[paulrosen]

Unfortunately the library isn't set up that way.

As a workaround, you could have each line of music be a separate ABC string so you could generate and draw the next line and get it ready to play, then when the onEnded callback happens on the previous line you start the new one.