Allow TTL to be reset atomically with incrememnt

Customer would like to be able to atomically incremement a key while extending it's TTL in the same operation.

the simplest example would be counting the number of requests in a session or IP.
on every incoming request we will increase the counter.
if we initially set the key with ~20min ttl, then even if requests keep on coming, the value will expire after this 20min.
We would like it this counter to expire only if there was no request for 20min.