@Override
    public JoinRow map(ResultSet r, StatementContext ctx) throws SQLException {
        return specialize(r, ctx).map(r, ctx);
    }
A {@link RowMapper} implementation to easily compose existing
RowMappers.  As the name implies, it is most commonly used
for retrieving multiple tables' Java representations from a
joined row.
core/src/main/java/org/jdbi/v3/core/mapper/JoinRowMapper.java