presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/PendingSplitsForPlanNode/getLifespan
class PendingSplitsForPlanNode:        public PendingSplits getLifespan(Lifespan lifespan)
        {
            return splitsByLifespan.computeIfAbsent(lifespan, ignored -> new PendingSplits());
        }