presto-main/src/main/java/io/prestosql/sql/planner/DistributedExecutionPlanner.java/DistributedExecutionPlanner/Visitor
class DistributedExecutionPlanner:        private Visitor(Session session, StageExecutionDescriptor stageExecutionDescriptor, ImmutableList.Builder<SplitSource> allSplitSources)
        {
            this.session = session;
            this.stageExecutionDescriptor = stageExecutionDescriptor;
            this.splitSources = allSplitSources;
        }