ex13 - https://medium.com/@lu4nm3/monad-transformers-vs-mtl-d3a1167e2649

ex13_mvm.scala

def main(): IO[(Vector[SystemState], SystemState)] = {
  for {
    monadReader <- createMonadReader(Env("127.0.0.1:8080"))
    monadWriter <- createMonadWriter[Vector[SystemState]]
    monadState <- createMonadState(SystemState(Map.empty[Env, Status]))
    result <- program(monadReader, monadWriter, monadState)
  } yield result
}