private ShareGroupHeartbeatResponse createShareGroupHeartbeatResponseWithError() {
        return new ShareGroupHeartbeatResponse(new ShareGroupHeartbeatResponseData()
                .setErrorCode(Errors.UNKNOWN_MEMBER_ID.code())
                .setMemberId(MEMBER_ID)
                .setMemberEpoch(5));
    }
Member that intentionally leaves the group (via unsubscribe) should release assignment,
reset epoch to -1, keep member ID, and transition to {@link MemberState#LEAVING} to send out a
heartbeat with the leave epoch. Once the heartbeat request is sent out, the member should
transition to {@link MemberState#UNSUBSCRIBED}
clients/src/test/java/org/apache/kafka/clients/consumer/internals/ShareMembershipManagerTest.java