@Override
    public RecordCursor cursor()
    {
        return new PrometheusRecordCursor(columnHandles, byteSource);
    }
@Test
    public void testCursorSimple()
    {
        RecordSet recordSet = new PrometheusRecordSet(
                new PrometheusClient(new PrometheusConnectorConfig(), METRIC_CODEC, TYPE_MANAGER),
                new PrometheusSplit(dataUri),
                ImmutableList.of(
                        new PrometheusColumnHandle("labels", varcharMapType, 0),
                        new PrometheusColumnHandle("timestamp", TIMESTAMP_WITH_TIME_ZONE, 1),
                        new PrometheusColumnHandle("value", DoubleType.DOUBLE, 2)));
        RecordCursor cursor = recordSet.cursor();

        assertEquals(cursor.getType(0), varcharMapType);
        assertEquals(cursor.getType(1), TIMESTAMP_WITH_TIME_ZONE);
        assertEquals(cursor.getType(2), DoubleType.DOUBLE);

        List<PrometheusStandardizedRow> actual = new ArrayList<>();
        while (cursor.advanceNextPosition()) {
            actual.add(new PrometheusStandardizedRow(
                    (Block) cursor.getObject(0),
                    ((Instant) cursor.getObject(1)),
                    cursor.getDouble(2)));
            assertFalse(cursor.isNull(0));
            assertFalse(cursor.isNull(1));
            assertFalse(cursor.isNull(2));
        }
        List<PrometheusStandardizedRow> expected = ImmutableList.<PrometheusStandardizedRow>builder()
                .add(new PrometheusStandardizedRow(getBlockFromMap(varcharMapType,
                        ImmutableMap.of("instance", "localhost:9090", "__name__", "up", "job", "prometheus")), ofEpochMilli(1565962969044L), 1.0))
                .add(new PrometheusStandardizedRow(getBlockFromMap(varcharMapType,
                        ImmutableMap.of("instance", "localhost:9090", "__name__", "up", "job", "prometheus")), ofEpochMilli(1565962984045L), 1.0))
                .add(new PrometheusStandardizedRow(getBlockFromMap(varcharMapType,
                        ImmutableMap.of("instance", "localhost:9090", "__name__", "up", "job", "prometheus")), ofEpochMilli(1565962999044L), 1.0))
                .add(new PrometheusStandardizedRow(getBlockFromMap(varcharMapType,
                        ImmutableMap.of("instance", "localhost:9090", "__name__", "up", "job", "prometheus")), ofEpochMilli(1565963014044L), 1.0))
                .build();
        List<PairLike<PrometheusStandardizedRow, PrometheusStandardizedRow>> pairs = Streams.zip(actual.stream(), expected.stream(), PairLike::new)
                .collect(Collectors.toList());
        pairs.forEach(pair -> {
            assertEquals(getMapFromBlock(varcharMapType, pair.getFirst().getLabels()), getMapFromBlock(varcharMapType, pair.getSecond().getLabels()));
            assertEquals(pair.getFirst().getTimestamp(), pair.getSecond().getTimestamp());
            assertEquals(pair.getFirst().getValue(), pair.getSecond().getValue());
        });
    }