HostName.connect races every resolved address through an Io.Group and cancels the losers — happy-eyeballs latency machinery. a relay reconnecting to thousands of hosts wants the smallest concurrency surface per connect, not per-connect latency: resolve, then try addresses one at a time on the subscriber fiber. no group spawns, no cancel storms in the hot path. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>