Eliminating Cold Starts 2: shard and conquer

What this post added

Introduced 'Worker sharding' using a consistent hash ring to route requests to existing Worker instances, reducing cold starts. This technique leverages the global network to coalesce requests onto specific servers, ensuring Workers remain warm and minimizing eviction. The implementation uses a consistent hash ring data structure, similar to that used in Cloudflare's HTTP cache, to dynamically map Worker script IDs to server addresses, allowing for graceful handling of server additions or removals.