presto-main/src/main/java/io/prestosql/operator/JoinBridgeManager.java/TaskWideInternalJoinBridgeDataManager/outerOperatorCreated
class TaskWideInternalJoinBridgeDataManager:        @Override
        public void outerOperatorCreated(Lifespan lifespan)
        {
            checkArgument(Lifespan.taskWide().equals(lifespan));
            joinLifecycle.retainForOuter();
        }