code: function(_body) {
      if(undefined === _body || null === _body) {
          return null;
      }
  
      if(_body instanceof Date || _body instanceof Error) {
          return _body;
      }
  
      if(util.isArray(_body)) {
          return _body.map(function(body) {
              return _formatSendBody(body);
          });
      }
  
      if(typeof _body === "object") {
          var res = {};
          for(var key in _body) {
              if(!_body.hasOwnProperty(key)) continue;
              res[key] = _formatSendBody(_body[key]);
          }
          return res;
      }
  
      if(typeof _body === "number" &&
         (isNaN(_body) || !isFinite(_body))) return null;
      return _body;
  }
docs: _formatSendBody
  @param {*} _body the body to be formatted
  @return {*} the body formatted