fn walk_dir_parallel(
dir: &Path,
depth: u32,
parent_dev: Option<u64>,
visited: &Arc<DashSet<PathBuf>>,
tx: &SyncSender<Vec<MidiFile>>,
found: &Arc<AtomicUsize>,
batch_size: usize,
stop: &Arc<AtomicBool>,
exclude: &Arc<HashSet<String>>,
active_dirs: &Arc<Mutex<Vec<String>>>,
incremental: Option<Arc<IncrementalDirState>>,
)