@Override
    public PollResult poll(long currentTimeMs) {
        if (state == MemberState.RECONCILING) {
            maybeReconcile();
        }
        return PollResult.EMPTY;
    }
Register a new listener that will be invoked whenever the member state changes, or a new
member ID or epoch is received.

@param listener Listener to invoke.
clients/src/main/java/org/apache/kafka/clients/consumer/internals/ShareMembershipManager.java