Tiered Cache Smart Topology

Introduced 'Smart Topology' for Tiered Cache, which automatically identifies the optimal data center for origin requests based on latency probing. This feature aims to maximize cache hit ratios by selecting a single proxying data center close to the origin. It includes a topology selection algorithm that uses a leaderboard of data center latencies, with a fallback to a generic topology when assumptions about origin location or Anycast networks are violated. The algorithm considers 24-hour median latency and includes a second-lowest latency data center as a fallback.