itimerspec instance containing the next expiration time. - it_value: the amount of time until the timer will next expire. If both fields are zero, then the timer is currently disarmed. Contains always a relative value. - it_interval: the interval of the timer. If both fields are zero, then the timer is set to expire just once, at the time specified by it_value.
upon failure to get the time from the timer fd
Returns the next expiration time.