presto-mongodb/src/main/java/io/prestosql/plugin/mongodb/ObjectIdType.java/ObjectIdType/getObjectValue
class ObjectIdType:    @Override
    public Object getObjectValue(ConnectorSession session, Block block, int position)
    {
        if (block.isNull(position)) {
            return null;
        }

        // TODO: There's no way to represent string value of a custom type
        return new SqlVarbinary(block.getSlice(position, 0, block.getSliceLength(position)).getBytes());
    }