@Override
    public <V> Map<String, Object> offset(Map<String, V> partition) {
        return offsets(Collections.singletonList(partition)).get(partition);
    }
@Test
    public void should_return_offset_for_existing_partition() {
        Map<String, String> partition = mapOf("part1", "something");
        Map<Map<String, ?>, Map<String, ?>> partitionToOffset = mapOf(partition, mapOf("part1", 123));
        State state = new State(partitionToOffset);
        JetSourceOffsetStorageReader sut = new JetSourceOffsetStorageReader(state);
        Map<String, Object> offset = sut.offset(partition);
        assertThat(offset).isEqualTo(mapOf("part1", 123));
    }