presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/GeometryType.java/GeometryType/writeSlice
class GeometryType:    @Override
    public void writeSlice(BlockBuilder blockBuilder, Slice value, int offset, int length)
    {
        if (value == null) {
            blockBuilder.appendNull();
            return;
        }
        blockBuilder.writeBytes(value, offset, length).closeEntry();
    }