void objc_setAssociatedObject(id object, const void *key, id value, objc_AssociationPolicy policy)
id objc_getAssociatedObject(id object, const void *key)
void objc_removeAssociatedObjects(id object)
數(shù)據(jù)結(jié)構(gòu)是2個嵌套的hashmap:
hashmap<object,hashmap<&key,value>>