protected function _logDelivery($contents)
    {
        if (empty($this->_profile['log'])) {
            return;
        }
        $config = [
            'level' => 'debug',
            'scope' => 'email'
        ];
        if ($this->_profile['log'] !== true) {
            if (!is_array($this->_profile['log'])) {
                $this->_profile['log'] = ['level' => $this->_profile['log']];
            }
            $config = $this->_profile['log'] + $config;
        }
        Log::write(
            $config['level'],
            PHP_EOL . $this->flatten($contents['headers']) . PHP_EOL . PHP_EOL . $this->flatten($contents['message']),
            $config['scope']
        );
    }