c client use a static global variable addr_rw_server to save a zhandle's member will cause problem if there are multiple zhandle connecting multiple ZooKeeper ensembles

static struct sockaddr_storage *addr_rw_server = 0;

// in ping_rw_server
addr_rw_server = rc ? &zh->addr_rw_server : 0; 

// in zookeeper_interest
if (addr_rw_server) {
    zh->addr_cur = *addr_rw_server;
    addr_rw_server = 0;
} else {
    // No need to delay -- grab the next server and attempt connection
    zoo_cycle_next_server(zh);
}