MuxedUpgrade = ref object of Upgrade
  muxers*: seq[MuxerProvider]
  streamHandler*: StreamHandler

proc identify(self: MuxedUpgrade; muxer: Muxer): Future[void] {....gcsafe,
    stackTrace: false, ...gcsafe, raises: [], raises: [], tags: [RootEffect].}

proc mux(self: MuxedUpgrade; conn: Connection): Future[Muxer] {....gcsafe,
    stackTrace: false, ...gcsafe, raises: [], raises: [], tags: [RootEffect].}

proc new(T: type MuxedUpgrade; identity: Identify; muxers: seq[MuxerProvider];
         secureManagers: openArray[Secure] = []; connManager: ConnManager;
         ms: MultistreamSelect): T:type {....raises: [].}

method upgradeIncoming(self: MuxedUpgrade; incomingConn: Connection): Future[
    void] {....gcsafe, stackTrace: false, ...gcsafe, raises: [], raises: [],
            tags: [RootEffect].}

method upgradeOutgoing(self: MuxedUpgrade; conn: Connection): Future[Connection] {.
    ...gcsafe, stackTrace: false, ...gcsafe, raises: [], raises: [],
    tags: [RootEffect].}