code: function ()
      {
          var bodyWrap = $build('body', {
              rid: this.rid++,
              xmlns: Strophe.NS.HTTPBIND
          });
  
          if (this.sid !== null) {
              bodyWrap.attrs({sid: this.sid});
          }
  
          return bodyWrap;
      }
docs: PrivateFunction: _buildBody
  _Private_ helper function to generate the <body/> wrapper for BOSH.
  
  Returns:
  A Strophe.Builder with a <body/> element.