fs.js

function delegateFunction(f) {
  return function() {
    var args = Array.prototype.slice.call(arguments);
    var last = args.pop();
    if (typeof last === 'function') {
      args.push(nodyn.vertxHandler(last));
    } else if (last !== undefined) {
      args.push(last);
    }
    f.apply(f, args);
  };
}
FS.rename     = delegateFunction(system.move);