/** Turn the body of this message into a child of itself if needed */
protected function becomeMimePart()
{
$part = new parent($this->getHeaders()->newInstance(), $this->getEncoder(), $this->getCache(), $this->getIdGenerator(), $this->userCharset);
$part->setContentType($this->userContentType);
$part->setBody($this->getBody());
$part->setFormat($this->userFormat);
$part->setDelSp($this->userDelSp);
$part->setNestingLevel($this->getTopNestingLevel());
return $part;
}
