Zeromq 1 to 1 async req-rep unreliable pattern

I have a 1 client to 1 server model, let's say the client will emit 100 req/s, but the server can only handle 50 req/s.
The client side is very tolerant. It says okay, I don't care about you dropping some of my requests, just process the latest one. What pattern should be applied in this situation?

Timeline ('<' denotes the server is processing the latest requests):
client: 1 -- 2 -- 3 -- 4 -- 5 -- 6 -- 7 -- 8 -- 9 -- 10
server:  <<<<<<<<<< 1 <<<<<<< 3 <<<<<<<<<<<< 5 <<<<<<< (processing 8)