private function initMailboxNames(): void
    {
        if (null !== $this->mailboxNames) {
            return;
        }

        $this->mailboxNames = [];
        $mailboxesInfo      = \imap_getmailboxes($this->resource->getStream(), $this->server, '*');
        if (!\is_array($mailboxesInfo)) {
            throw new ImapGetmailboxesException('imap_getmailboxes failed');
        }

        foreach ($mailboxesInfo as $mailboxInfo) {
            $name                      = \mb_convert_encoding(\str_replace($this->server, '', $mailboxInfo->name), 'UTF-8', 'UTF7-IMAP');
            $this->mailboxNames[$name] = $mailboxInfo;
        }
    }