private static bool isBusy = false;
private static Queue<IntPtr> pendingHandles = new Queue<IntPtr>();

public static void Run(IntPtr windowHandle) {
    pendingHandles.Enqueue(windowHandle);
    if (isBusy) { return; }

    isBusy = true;

    if (Cache == null || Cache.MonitorCount != BFS.Monitor.GetMonitorCountEnabled()) {
        ResetCache();
    }

    while (pendingHandles.TryDequeue(out nint handle)) {
        try {
            ExecAction(handle);
        }
        catch (Exception e)
        {
            BFS.Audio.PlayWAV("U:\\Sounds\\notifications-wav\\Windows - Default Beep.wav");
            ResetCache();
        }
    }
    isBusy = false;
}

record CachedData(int MonitorCount, Rectangle PrimaryArea, Rectangle[] WorkAreas, Rectangle[][] SubAreas, Rectangle[] SubDivisions);

private static CachedData Cache = null;

private static void ResetCache() {
    int count = BFS.Monitor.GetMonitorCountEnabled();
    var primary = BFS.Monitor.GetPrimaryMonitorWorkArea();
    var workAreas = BFS.Monitor.GetMonitorWorkAreas();
    if (CycleLeft) { Array.Reverse(workAreas); }
    var subareas = workAreas.Select(static x => x.GetSubdivisions()).ToArray();
    var subdivs = subareas.SelectMany(static x => x).ToArray();
    Cache = new CachedData(count, primary, workAreas, subareas, subdivs);
}