presto-hive/src/main/java/io/prestosql/plugin/hive/util/HiveWriteUtils.java/BinaryFieldSetter/setField
class BinaryFieldSetter:        @Override
        public void setField(Block block, int position)
        {
            byte[] bytes = VarbinaryType.VARBINARY.getSlice(block, position).getBytes();
            value.set(bytes, 0, bytes.length);
            rowInspector.setStructFieldData(row, field, value);
        }