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

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

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

method upgrade(self: MuxedUpgrade; conn: Connection; direction: Direction;
               peerId: Opt[PeerId]): Future[Muxer] {.stackTrace: false, ...gcsafe,
    raises: [], raises: [], raises: [], tags: [RootEffect].}