signature MLTON_ITIMER =
   sig
      datatype t =
         Prof
       | Real
       | Virtual

      val set: t * {interval: Time.time, value: Time.time} -> unit
      val signal: t -> Posix.Signal.signal
   end

• set (t, {interval, value})
  sets the interval timer (using setitimer) specified by t to the given interval and value.

• signal t
  returns the signal corresponding to t.