title: Dartlang wait more than one future
body: <p>I want to do something after a lot of future functions are done, but I do not know how to write the code in dart?
  the code is like this:</p>
  <pre><code>for (var d in data) {
    d.loadData().then()
  }
  // when all loaded
  // do something here
  </code></pre>
  <p>but I don't want to wait for them one by one:</p>
  <pre><code>for (var d in data) {
    await d.loadData(); // NOT NEED THIS
  }
  </code></pre>
  <p>how to write those code in dart?</p>