title: how to get Extjs 4 store's request data on beforeload event?
body: <p>I'm trying to get request data params beforeload event on store. I can see the operation object contains the request data but I can't seems to get it from operation object</p>
  
  <pre><code>Ext.create('Ext.data.Store', {
      autoLoad : true,
      fields   : [
          {name: 'item_code',             type: 'string'},
          {name: 'quantity',              type: 'int'},
          {name: 'description',           type: 'string'}
      ],
      storeId  : 'summary',
      proxy    : {
          type            : 'ajax',
          actionMethods   : 'POST',
          extraParams     : {'filter': 'branch', 'branch': location },        
          url             : 'reports/stock_summary',
          reader: {
              type    : 'json',
              root    : 'data'
          }
      },
      listeners: {
          beforeload: function(store, operation, options){
              console.log( operation )
          }
      }
  });
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/jIwx0.jpg" alt="firebug"></p>
  
  <p>any idea how to get request object on before load event and get data inside of that request object?</p>