[feature] Publish audio from file or stream from file

[haohmaruru]

Hello LiveKit SDK Flutter Team,

I've been using this SDK for a while, and I'm looking to implement a feature that allows me to publish audio from a local audio file (ex: .opus,.wav, .mp3... file) from the sender's machine so that everyone else in the room can hear it. Alternatively, I'd like to explore the possibility of capturing a streaming record from another SDK like scrcpy (https://github.com/Genymobile/scrcpy) and publishing that stream into the room.

I'm looking forward to your prompt response.

Thank you very much.