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    <h3>Editing: DateHeader.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Mime\Header;

/**
 * A Date MIME Header.
 *
 * @author Chris Corbyn
 */
final class DateHeader extends AbstractHeader
{
    private \DateTimeImmutable $dateTime;

    public function __construct(string $name, \DateTimeInterface $date)
    {
        parent::__construct($name);

        $this-&gt;setDateTime($date);
    }

    /**
     * @param \DateTimeInterface $body
     */
    public function setBody(mixed $body)
    {
        $this-&gt;setDateTime($body);
    }

    public function getBody(): \DateTimeImmutable
    {
        return $this-&gt;getDateTime();
    }

    public function getDateTime(): \DateTimeImmutable
    {
        return $this-&gt;dateTime;
    }

    /**
     * Set the date-time of the Date in this Header.
     *
     * If a DateTime instance is provided, it is converted to DateTimeImmutable.
     */
    public function setDateTime(\DateTimeInterface $dateTime)
    {
        if ($dateTime instanceof \DateTime) {
            $immutable = new \DateTimeImmutable('@'.$dateTime-&gt;getTimestamp());
            $dateTime = $immutable-&gt;setTimezone($dateTime-&gt;getTimezone());
        }
        $this-&gt;dateTime = $dateTime;
    }

    public function getBodyAsString(): string
    {
        return $this-&gt;dateTime-&gt;format(\DateTime::RFC2822);
    }
}
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