title: Why does backbone.js model.save() change the attribute hash?
body: <p>I am doing something like this in my code:</p>
  
  <pre><code>data_hash = {};
  data_hash['some_model_key'] = 'A';
  console.log(data_hash['some_model_key']); /* prints A */
  model.save(data_hash,{
      wait:true,
      success:function(){
          console.log(data_hash['some_model_key']); /* prints B */
      }
  });                  
  </code></pre>
  
  <p>I understand that if the server changes the state of the model and i am setting <code>wait:true</code> then my backbone model should receive the new value.  But why is my attribute hash being changed?</p>