src/Message.php
public function getHeaderLine($name)
    {
        if ( ! isset($this->_headers[$name]))
        {
            return '';
        }

        return implode(', ', $this->_headers[$name]);
    }
public function getHeaderLine($name)
    {
        if ( ! isset($this->_headers[$name]))
        {
            return '';
        }

        return implode(', ', $this->_headers[$name]);
    }
{@inheritdoc}