lib/classes/Swift/Mime/SimpleMessage.php
public function setDate(DateTimeInterface $dateTime)
    {
        if (!$this->setHeaderFieldModel('Date', $dateTime)) {
            $this->getHeaders()->addDateHeader('Date', $dateTime);
        }

        return $this;
    }
public function setDate(DateTimeInterface $dateTime)
    {
        if (!$this->setHeaderFieldModel('Date', $dateTime)) {
            $this->getHeaders()->addDateHeader('Date', $dateTime);
        }

        return $this;
    }
public function setDate ( DateTimeInterface $ dateTime ) { if ( ! $ this -> setHeaderFieldModel ( 'Date' , $ dateTime ) ) { $ this -> getHeaders ( ) -> addDateHeader ( 'Date' , $ dateTime ) ; } return $ this ; }
Set the date at which this message was created.

@return $this
Set the date at which this message was created .