Struct SubscriberSet 

pub struct SubscriberSet { /* private fields */ }

Fan-out coordinator for multiple event subscribers.

Manages per-subscriber queues and worker tasks, providing:

• Concurrent delivery: events are sent to all subscribers simultaneously
• Isolation: each subscriber has a dedicated queue and worker
• Panic safety: panics are caught and reported, do not crash the runtime
• Overflow handling: dropped events are reported via SubscriberOverflow

Implementations

impl SubscriberSet

pub fn new(subs: Vec<Arc<dyn Subscribe>>, bus: Bus) -> Self

Creates a new set and spawns one worker task per subscriber.

Per-subscriber setup

• Bounded mpsc queue (capacity from Subscribe::queue_capacity, clamped to >= 1)
• Dedicated worker task (runs until the queue is closed)
• Panic isolation via catch_unwind

Notes

• Workers start immediately and process events until shutdown

pub fn emit(&self, event: &Event)

Emits an event to all subscribers (clones the event).

• Clones the event, wraps it in Arc, then calls emit_arc
• Returns immediately (non-blocking)

Notes

For hot paths, prefer emit_arc to avoid cloning.

pub fn emit_arc(&self, event: Arc<Event>)

Emits a pre-allocated Arc<Event> to all subscribers.

• Uses try_send (non-blocking)
• On queue full: drops the event, publishes SubscriberOverflow
• On queue closed: publishes SubscriberOverflow with reason “closed”

Overflow prevention

Prevents infinite loops and event storms: if the incoming event is SubscriberOverflow or SubscriberPanicked, we do not publish further overflow diagnostics for it.

pub async fn shutdown(self)

Gracefully shuts down all subscriber workers.

• Drops all channel senders (workers observe channel closure),
• Awaits all worker tasks to finish.