* @return
* NULL if no key matches the input,
* a value associated with a matching key otherwise.
* @return
* NULL if no key matches the input,
* a value associated with a matching key otherwise.
* The rte_kvargs structure
* @param key_match
* The key that should match, or NULL to count all associations
* The rte_kvargs structure
* @param key_match
* The key that should match, or NULL to count all associations