zone.fork({
  afterTask: function () {
    // do some cleanup
  }
}).run(function () {
  // do stuff
});

function schedule() {
  setTimeout(function() { console.log('setTimeout')}, 0);
  Promise.resolve('promise')
    .then(function(_) { console.log(_); return 'then'; })
    .then(function(_) { console.log(_); })
  ;
}

zone
  .fork({
    afterTask: function () { console.log('vm turn end'); }
  })
  .run(schedule);