Mostly for inspiration, requires (probably...) some manual installation at the moment.
Spotify tmux code: https://github.com/LiveNL/spotify-tmux-applescript
https://apple.stackexchange.com/questions/10467/how-to-increase-keyboard-key-repeat-rate-on-os-x
defaults write -g InitialKeyRepeat -int 10 # normal minimum is 15 (225 ms)
defaults write -g KeyRepeat -int 1 # normal minimum is 2 (30 ms)