protected function initialize()
    {
        parent::initialize();

        // unless already configured, set default options to include exceptions
        $options = $this->defaults->getOptions() ?: [];

        foreach ($this->soapOptionDefaults as $option => $value) {

            if ( ! array_key_exists($option, $options)) {

                $options[ $option ] = $value;
            }
        }

        $this->defaults->setOptions($options);
    }