svoid onFileChange(double seconds, File file, long lastModificationSeen default modificationTime(file), Runnable r) {
  doEvery_daemon(toMS(seconds), new Runnable {
    long lastMod = lastModificationSeen;
    
    run {
      long mod = modificationTime(file);
      if (mod != lastMod) {
        lastMod = mod;
        call(r);
      }
    }
  });
  
  call(r);
}