filter_type_t filter_register(const char *type, filter_constructor_t constructor,
filter_destructor_t destructor, filter_runner_t runner,
filter_context_constructor_t context_constructor,
filter_type_t filter_register(const char *type, filter_constructor_t constructor,
filter_destructor_t destructor, filter_runner_t runner,
filter_context_constructor_t context_constructor,