Interface PublishOptions

Targeted ack: only an ack from THIS user id clears the retry — acks from other receivers are ignored. Use when one specific peer must receive the message (e.g. an authoritative writer that persists it), so a bystander's ack can't mask a lost delivery to the peer that matters. Retries continue until the target acks or the retry budget exhausts (then onError fires as usual).

Must exactly match the target's relay user id (the id it joined the relay with). Implies requireAck: true unless explicitly disabled. Every receiver still sends an ack — the sender simply ignores the ones that aren't from the target — so mixed-version peers are unaffected.

Override the hook's default ack policy for this single message. false = fire-and-forget (no retry, no ack). Use for high-rate ephemeral signals where loss is acceptable (cursor positions, laser pointer).