uint64_t ht_cas (hashtable_t *ht, void *key, uint64_t expected_val, uint64_t val);
uint64_t ht_get (hashtable_t *ht, void *key);
uint64_t ht_remove (hashtable_t *ht, void *key);
uint64_t ht_cas (hashtable_t *ht, void *key, uint64_t expected_val, uint64_t val);
uint64_t ht_get (hashtable_t *ht, void *key);
uint64_t ht_remove (hashtable_t *ht, void *key);