function after(n, func) {
    if (n < 1) {
      return func();
    }
    return function() {
      if (--n < 1) {
        return func.apply(this, arguments);
      }
    };
  }
Creates a new function that is restricted to executing only after it is
called `n` times.

@static
@memberOf _
@category Functions
@param {Number} n The number of times the function must be called before
it is executed.
@param {Function} func The function to restrict.
@returns {Function} Returns the new restricted function.
@example

var renderNotes = _.after(notes.length, render);
_.forEach(notes, function(note) {
  note.asyncSave({ 'success': renderNotes });
});
// `renderNotes` is run once, after all notes have saved