public boolean completeJoinFuture(
        ClassicGroupMember member,
        JoinGroupResponseData response
    ) {
        if (member.isAwaitingJoin()) {
            member.awaitingJoinFuture().complete(response);
            member.setAwaitingJoinFuture(null);
            numMembersAwaitingJoinResponse--;
            return true;
        }
        return false;
    }
Complete the join future.

@param member    the member.
@param response  the join response to complete the future with.
@return true if a join future actually completes.
group-coordinator/src/main/java/org/apache/kafka/coordinator/group/classic/ClassicGroup.java