You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: keyword.rs
    path of file: ./repos/mail-server/crates/jmap-proto/src/types
    
    the code of the file until where you have to start completion: /*
 * Copyright (c) 2023 Stalwart Labs Ltd.
 *
 * This file is part of Stalwart Mail Server.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 * in the LICENSE file a
    
    fn serialize(self) -> Vec<u8> {
        match self {
            Keyword::Seen => vec![SEEN as u8],
            Keyword::Draft => vec![DRAFT as u8],
            Keyword::Flagged => vec![FLAGGED as u8],
            Keyword::Answered => vec![ANSWERED as u8],
            Keyword::Recent => vec![RECENT as u8],
            Keyword::Important => vec![IMPORTANT as u8],
            Keyword::Phishing => vec![PHISHING as u8],
            Keyword::Junk => vec![JUNK as u8],
            Keyword::NotJunk => vec![NOTJUNK as u8],
            Keyword::Deleted => vec![DELETED as u8],
            Keyword::Forwarded => vec![FORWARDED as u8],
            Keyword::MdnSent => vec![MDN_SENT as u8],
            Keyword::Other(string) => string.as_bytes().to_vec(),
        }
    }