This post is part of F# Advent calender. Thanks Sergey Tihon for arranging this and giving me chance. First I like to clarify that this was not my original choice for FSAdvent calender. I was going to write long post about web, AKKA, api and real time system. My current working area. But this time’s calender entries are reaching new level and dimension. And recent post from Evelina Gabasova is kind of reason behind change.