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Squid v2.x (not 3.x as far as I can tell?) has a feature they coined Collapsed Forwarding. In a nutshell, it allows the intermediary to piggy back multiple clients on a single origin server connections. There are a few ways we could accomplish this, but they all would share the same property: this is only safe to do for cacheable objects.

Problem space and issues

The problem to solve is a form of stampeding heard: When a cached object goes stale, instead of potentially letting 100's or 1000's of requests slip through to the origin, we want to minimize this as much as possible. In a best case scenario,  a redux to 1 origin connection could be achieved. One issue here is to know if a request is cacheable (and therefore shareable). On a complete cache miss (cold cache), this can be difficult at best. On a cache

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