+/* prototypes to avoid warnings */
+void hashset_init(HashSet *self);
+void hashset_destroy(HashSet *self);
+size_t hashset_size(const HashSet *self);
+InsertReturnValue hashset_insert(HashSet *self, KeyType key);
+InsertReturnValue hashset_find(const HashSet *self, ConstKeyType key);
+void hashset_remove(HashSet *self, ConstKeyType key);
+void hashset_init_size(HashSet *self, size_t expected_elements);
+void hashset_iterator_init(HashSetIterator *self, const HashSet *hashset);
+ValueType hashset_iterator_next(HashSetIterator *self);
+void hashset_remove_iterator(HashSet *self, const HashSetIterator *iter);
+