mp3rgain - ReplayGain implementation using symphonia

[M-Igashi]

Hi! I wanted to share that I've used symphonia for mp3rgain,
a modern mp3gain replacement written in Rust.

symphonia enables our ReplayGain analysis feature, which decodes
MP3 files to calculate perceived loudness.

Project: https://github.com/M-Igashi/mp3rgain

Thanks for this excellent library!