lib/components/web/widgets/Widget.php
public function setState($key, $value)
    {
        return Yii::$app->webState->set($this->stateKeyName($key), $value);
    }
public function setState($key, $value)
    {
        return Yii::$app->webState->set($this->stateKeyName($key), $value);
    }
Set state.

@param [[@doctodo param_type:key]]   $key   [[@doctodo param_description:key]]
@param [[@doctodo param_type:value]] $value [[@doctodo param_description:value]]

@return [[@doctodo return_type:setState]] [[@doctodo return_description:setState]]