public Set<MemberToRemove> members() {
        return members;
    }
@Test
    public void testConstructor() {
        RemoveMembersFromConsumerGroupOptions options = new RemoveMembersFromConsumerGroupOptions(
            Collections.singleton(new MemberToRemove("instance-1")));

        assertEquals(Collections.singleton(
            new MemberToRemove("instance-1")), options.members());

        // Construct will fail if illegal empty members provided
        assertThrows(IllegalArgumentException.class, () -> new RemoveMembersFromConsumerGroupOptions(Collections.emptyList()));
    }