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

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]): InternalRaisesFuture[
    Muxer, (CancelledError, LPError)] {.stackTrace: false, ...raises: [], gcsafe,
                                        raises: [], raises: [],
                                        tags: [RootEffect].}