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

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