public function customSetting(string $settingKey, $settingValue): self
    {
        $this->clientConfig[$settingKey] = $settingValue;
        return $this;
    }
public function customSetting(string $settingKey, $settingValue): self
    {
        $this->clientConfig[$settingKey] = $settingValue;
        return $this;
    }
public function customSetting ( string $ settingKey , $ settingValue ) : self { $ this -> clientConfig [ $ settingKey ] = $ settingValue ; return $ this ; }
add or modify client config by custom
@return self
add or modify client config by custom