-uint64_t sl_lookup (skiplist_t *sl, uint64_t key);
-uint64_t sl_add (skiplist_t *sl, uint64_t key, uint64_t value);
-uint64_t sl_remove (skiplist_t *sl, uint64_t key);
+uint64_t sl_lookup (skiplist_t *sl, const void *key_data, uint32_t key_len);
+uint64_t sl_add (skiplist_t *sl, const void *key_data, uint32_t key_len, uint64_t value);
+uint64_t sl_remove (skiplist_t *sl, const void *key_data, uint32_t key_len);