def start_and_service_times(self):
        return [(x.scheduler_launch_time, x.service_time()) for x in self.__tasks.values()
                if x.complete()]
Returns a list of (start time, service time) tuples for complete __tasks.
dataset/ETHPy150Open radlab/sparrow/src/main/python/parse_logs.py/Request.start_and_service_times