lib/classes/Swift/Message.php
public function addPart($body, $contentType = null, $charset = null)
    {
        return $this->attach((new Swift_MimePart($body, $contentType, $charset))->setEncoder($this->getEncoder()));
    }
public function addPart($body, $contentType = null, $charset = null)
    {
        return $this->attach((new Swift_MimePart($body, $contentType, $charset))->setEncoder($this->getEncoder()));
    }
public function addPart ( $ body , $ contentType = null , $ charset = null ) { return $ this -> attach ( ( new Swift_MimePart ( $ body , $ contentType , $ charset ) ) -> setEncoder ( $ this -> getEncoder ( ) ) ) ; }
Add a MimePart to this Message.

@param string|Swift_OutputByteStream $body
@param string                        $contentType
@param string                        $charset

@return $this
Add a MimePart to this Message .