|null $flags */ public function __construct( string $mailboxName, private string $message, ?array $flags, ?DateTimeInterface $internalDate ) { parent::__construct( 'APPEND', ...array_filter([ new QuotedString($mailboxName), ParenthesizedList::tryFrom($flags), DateTime::tryFrom($internalDate), new SynchronizingLiteral($this->message), ]) ); } public function continue(): string { return $this->message; } }