presto-hive/src/main/java/io/prestosql/plugin/hive/HivePageSource.java/ListCoercer/apply
class ListCoercer:        @Override
        public Block apply(Block block)
        {
            if (elementCoercer == null) {
                return block;
            }
            ColumnarArray arrayBlock = toColumnarArray(block);
            Block elementsBlock = elementCoercer.apply(arrayBlock.getElementsBlock());
            boolean[] valueIsNull = new boolean[arrayBlock.getPositionCount()];
            int[] offsets = new int[arrayBlock.getPositionCount() + 1];
            for (int i = 0; i < arrayBlock.getPositionCount(); i++) {
                valueIsNull[i] = arrayBlock.isNull(i);
                offsets[i + 1] = offsets[i] + arrayBlock.getLength(i);
            }
            return ArrayBlock.fromElementBlock(arrayBlock.getPositionCount(), Optional.of(valueIsNull), offsets, elementsBlock);
        }