servePlayer ∷ StateT (Maybe TrackInfo) (Reader (LFMConfig, Player)) (IO ())
servePlayer = do
  (c, ρ) ← ask
  maybeOldTrack ← get
  threadDelayS fetchDelay

----

    Couldn't match expected type `StateT
                                    (Maybe TrackInfo) (Reader (LFMConfig, Player)) a0'
                with actual type `IO ()'
    In the return type of a call of `threadDelayS'
    In a stmt of a 'do' block: threadDelayS fetchDelay