You have 100 requests/second of location info(Like lattitude and longitude) coming from your application user.
You have to hit the external GPS service providers like google to get the adress of that request. But the 3rd party providers have rate limiting of 10 requests/second. So they can only servce 10 requests per second, More that that, they will reject the requests.
How do you design the systems so that the number of requests in your system queue wont build up and slows down your system?