class BeamFnDataGrpcMultiplexer {

  public StreamObserver<BeamFnApi.Elements> getOutboundObserver() {
    return outboundObserver;
  }

  public  BeamFnDataGrpcMultiplexer(
      Endpoints.ApiServiceDescriptor apiServiceDescriptor,
      Function<StreamObserver<BeamFnApi.Elements>,
               StreamObserver<BeamFnApi.Elements>> outboundObserverFactory);

}