This is how many HTTP caches and CDNs work. The terminology used to describe it is often request collapsing or request coalescing.

Some examples:

* varnish: https://info.varnish-software.com/blog/hit-for-pass-varnish-...

* nginx: http://nginx.org/en/docs/http/ngx_http_proxy_module.html#pro...

* fastly: https://docs.fastly.com/guides/performance-tuning/request-co...

* cloudfront: https://docs.aws.amazon.com/AmazonCloudFront/latest/Develope...