func defaultMsgIdProvider(m: Message): Result[MessageId, ValidationResult] {.
    ...raises: [], tags: [].}

proc init(T: type Message; peer: Option[PeerInfo]; data: seq[byte];
          topic: string; seqno: Option[uint64]; sign: bool = true): Message {.
    ...gcsafe, raises: [LPError], raises: [].}

proc init(T: type Message; peerId: PeerId; data: seq[byte]; topic: string;
          seqno: Option[uint64]): Message {....gcsafe, raises: [LPError],
    raises: [].}

proc sign(msg: Message; privateKey: PrivateKey): CryptoResult[seq[byte]] {.
    ...raises: [], tags: [RootEffect].}

proc verify(m: Message): bool {....raises: [], tags: [RootEffect].}