The default host pubsub: core's in-process EventEmitterPubSub, which is
exactly right inside a DO (one isolate, no cross-process delivery to lose)
and is what core itself would default to per createRun — the difference is
that this one instance is SHARED, so publish and replay agree.
A host opts in with init(env, { pubsub: createHostPubSub() }), the same
instance-or-absent shape every other InitOptions seam takes (storage,
resumeLedger, requestContextForRun).
The default host pubsub: core's in-process
EventEmitterPubSub, which is exactly right inside a DO (one isolate, no cross-process delivery to lose) and is what core itself would default to per createRun — the difference is that this one instance is SHARED, so publish and replay agree.A host opts in with
init(env, { pubsub: createHostPubSub() }), the same instance-or-absent shape every other InitOptions seam takes (storage,resumeLedger,requestContextForRun).