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

proc new(T: type MuxedUpgrade; muxers: seq[MuxerProvider];
         secureManagers: openArray[Secure] = []; ms: MultistreamSelect;
         connManager: Opt[ConnManager] = Opt.none(ConnManager)): T:type {.
    ...raises: [].}

method upgrade(self: MuxedUpgrade; conn: RawConn; peerId: Opt[PeerId]): InternalRaisesFuture[
    Muxer, (CancelledError, LPError)] {....stackTrace: false, raises: [], gcsafe,
                                        raises: [], tags: [RootEffect],
                                        forbids: [].}