presto-main/src/main/java/io/prestosql/sql/planner/optimizations/PruneUnreferencedOutputs.java/PruneUnreferencedOutputs/visitOffset
class PruneUnreferencedOutputs:        @Override
        public PlanNode visitOffset(OffsetNode node, RewriteContext<Set<Symbol>> context)
        {
            ImmutableSet.Builder<Symbol> expectedInputs = ImmutableSet.<Symbol>builder()
                    .addAll(context.get());
            PlanNode source = context.rewrite(node.getSource(), expectedInputs.build());
            return new OffsetNode(node.getId(), source, node.getCount());
        }