title: Dart Performance when initializing a list with items
body: <p>What is more performant?</p>
  <pre><code>[
      for(var item in items)
          ...
  ]
  </code></pre>
  <p>or</p>
  <pre><code>items.map((e) =&gt; ...).toList();
  </code></pre>
  <p>Of course those example are <em>very</em> minimalistic. But I wonder what would be more performant if you have many items and a lot of logic to build the list.</p>