private static Stream<Arguments> notInGroupStates() {
        return Stream.of(
            Arguments.of(MemberState.UNSUBSCRIBED),
            Arguments.of(MemberState.FENCED),
            Arguments.of(MemberState.FATAL),
            Arguments.of(MemberState.STALE));
    }
@return States where the member is not part of the group.
clients/src/test/java/org/apache/kafka/clients/consumer/internals/MembershipManagerImplTest.java