Interact with PulseAudio via Dart FFI.

Works only in Linux with PulseAudio (or pipewire-pulse) running.

• In Debug mode hot reload and hot restart don't work (see #1)

If another version of libpulse has been released with a breaking change updating the FFI bindings could be necessary.

$ git submodule update --init --recursive

$ flutter pub run ffigen --config ffigen.yaml