I've read your interesting article about [Transducers](http://raganwald.com/2017/04/30/transducers.html) and I've posted a [question on SO](http://stackoverflow.com/questions/44022945/function-composition-with-rest-operator-reducer-and-mapper). I'm sure you could help answering this. By the way, this is a [gist with C# porting](https://gist.github.com/giuliohome/fe082cdd508a12c877709e1134685ed9)