Big fan of request coalescing, was introduced to it by Varnish. Really helps when a cache entry drops. I believe what the article did is called a "grace period

Big fan of request coalescing, was introduced to it by Varnish. Really helps when a cache entry drops. I believe what the article did is called a "grace period". Are there any open implementations of distributed request coalescing? Pretty easy to do using a service proxy, but what about something like a Raft cluster?