ULONGLONG
KeQueryTimerDueTime(
  IN  PKTIMER Timer
  );

Routine Description:

    This function returns the InterruptTime at which the timer is
    pending.   0 is returned if the timer is not pending.

    N.B. This function may only be called by the system sleep code.

Arguments:

    Timer - Supplies a pointer to a dispatcher object of type timer.

Return Value:

    Returns the amount of time remaining on the timer, or 0 if the
    timer is not pending.