presto-main/src/main/java/io/prestosql/operator/project/DictionaryAwarePageProjection.java/DictionaryAwarePageProjection/DictionaryAwarePageProjectionWork
class DictionaryAwarePageProjection:        public DictionaryAwarePageProjectionWork(@Nullable ConnectorSession session, DriverYieldSignal yieldSignal, Page page, SelectedPositions selectedPositions)
        {
            this.session = session;
            this.block = requireNonNull(page, "page is null").getBlock(0);
            this.selectedPositions = requireNonNull(selectedPositions, "selectedPositions is null");
            this.produceLazyBlock = DictionaryAwarePageProjection.this.produceLazyBlock && !block.isLoaded();

            if (produceLazyBlock) {
                this.yieldSignal = NON_YIELDING_SIGNAL;
            }
            else {
                this.yieldSignal = requireNonNull(yieldSignal, "yieldSignal is null");
                setupDictionaryBlockProjection();
            }
        }