presto-main/src/main/java/io/prestosql/execution/SqlTaskExecution.java/SqlTaskExecution/getAndSetDriversForDriverGroupLifeCycleScheduled
class SqlTaskExecution:        public boolean getAndSetDriversForDriverGroupLifeCycleScheduled()
        {
            if (unpartitionedDriversScheduled) {
                return true;
            }
            unpartitionedDriversScheduled = true;
            return false;
        }