code: public function setSearchParams($params)
      {
          if ($params instanceof \Traversable) {
              $params = ArrayUtils::iteratorToArray($params);
          }
  
          $params = Json::encode($params);
          $this->setAttribute('data-search-params', $params);
  
          return $this;
      }
docs: Sets the initial search params.
  
  That means, the values for the elements
  which should be set, if the form resets.
  
  @param array|\Traversable $params
  
  @return self