uint64_t sl_cas (skiplist_t *sl, void *key, uint64_t expected_val, uint64_t new_val);
uint64_t sl_lookup (skiplist_t *sl, void *key);
uint64_t sl_remove (skiplist_t *sl, void *key);
uint64_t sl_count (skiplist_t *sl);
void sl_print (skiplist_t *sl);
void sl_free (skiplist_t *sl);
uint64_t sl_cas (skiplist_t *sl, void *key, uint64_t expected_val, uint64_t new_val);
uint64_t sl_lookup (skiplist_t *sl, void *key);
uint64_t sl_remove (skiplist_t *sl, void *key);
uint64_t sl_count (skiplist_t *sl);
void sl_print (skiplist_t *sl);
void sl_free (skiplist_t *sl);