presto-jdbc/src/main/java/io/prestosql/jdbc/PrestoDatabaseMetaData.java/PrestoDatabaseMetaData/unwrap
class PrestoDatabaseMetaData:    @SuppressWarnings("unchecked")
    @Override
    public <T> T unwrap(Class<T> iface)
            throws SQLException
    {
        if (isWrapperFor(iface)) {
            return (T) this;
        }
        throw new SQLException("No wrapper for " + iface);
    }