private static BidiFlow<long, int, string, ByteString, NotUsed> Inverse()
{
return
BidiFlow.FromFlows(
Flow.Create<long>().Select(x => ((int)x) + 2).WithAttributes(Attributes.CreateName("top")),
Flow.Create<string>()
.Select(ByteString.FromString)
.WithAttributes(Attributes.CreateName("bottom")));
}