Functionaly pure message passing

[Crowdhailer]

@mjadczak

So, when you say that your module makes it possible to send multiple ‘replies’, it doesn’t.

In my original PairUp example I send zero replies in response to the first call and two in response to the second call.

@mjadczak

Firstly, you can actually inspect all messages flowing through a system using built-in BEAM functions

I should have been more explicit. I want to reason about messages at compile time.