title: Update Backbone.Model after Backbone.sync
body: <p>I try to send requests with <code>Backbone.sync</code>:</p>
  
  <pre><code>...
  async createModel(model) {
    await Backbone.sync('create'/*or 'update' or 'delete'*/, model); 
    console.log(model.toJSON());
    model.fetch(); // i don't want to do this
  }
  ...
  </code></pre>
  
  <p>After <code>.sync('...')</code> server responses with some data, but that data is not the same as <code>model.toJSON()</code>, so I need extra <code>.fetch()</code> method to correctly update my model. </p>
  
  <p>Why it happens? How can I update my model right after <code>.sync()</code> without extra <code>.fetch()</code>? <code>{wait: true}</code> option doesn't help.</p>