Event-loop turns run to completion, so I/O on shared, remote, or slow state belongs between turns (async); synchronous access is fine only for state local, prompt, and private to the actor, such as a Durable Object's SQLite. Sourced from Miller, Tribble & Shapiro, "Concurrency Among Strangers" (TGC 2005), §5.2 and §6 footnote 5. Generated-by: Claude Opus 5.5