presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/Status/per
class Status:        @GuardedBy("this")
        private PerLifespanStatus per(Lifespan lifespan)
        {
            if (perLifespan.containsKey(lifespan)) {
                return perLifespan.get(lifespan);
            }
            PerLifespanStatus result = new PerLifespanStatus();
            perLifespan.put(lifespan, result);
            return result;
        }