hiredis assertion fails with no callbacks

gistfile1.c

int main (int argc, char **argv) {
        int i = 0;
        signal(SIGPIPE, SIG_IGN);
        struct event_base *base = event_base_new();

        redisAsyncContext *c = redisAsyncConnect("127.0.0.1", 6379);
        redisAsyncContext *c2 = redisAsyncConnect("127.0.0.1", 6379);

        if (c->err) {
                /* Let *c leak for now... */
                printf("main: Error: %s\n", c->errstr);
                return 1;
        }
        if (c2->err) {
                /* Let *c leak for now... */
                printf("main: Error: %s\n", c2->errstr);
                return 1;
        }

        redisLibeventAttach(c,base);
        redisLibeventAttach(c2,base);

        redisAsyncSetConnectCallback(c,connectCallback);
        redisAsyncSetDisconnectCallback(c,disconnectCallback);
        redisAsyncSetConnectCallback(c2,connectCallback);
        redisAsyncSetDisconnectCallback(c2,disconnectCallback);

        event_base_dispatch(base);

        return 0;
}