event

type Event struct {
	// Topic names the stream this event belongs to. Required.
	Topic string `json:"topic"`

	// Key determines ordering. Events sharing a key are delivered to consumers
	// in publish order; events with different keys have no relative ordering
	// guarantee, because a broker is free to place them on separate partitions.
	// The key is therefore a domain decision — it declares what must stay
	// ordered with respect to what — and is required for that reason.
	Key string `json:"key"`

	// ID uniquely identifies this event and is the basis for consumer-side
	// deduplication. Delivery is at-least-once, so a consumer may see the same
	// ID more than once and must treat a repeat as a no-op.
	//
	// It is generated once, when the event is created, and must survive a
	// republish unchanged — an ID minted at publish time would differ on every
	// retry and defeat deduplication entirely.
	ID string `json:"id"`

	// OccurredAt is when the event happened, which is not necessarily when it
	// was published or consumed.
	OccurredAt time.Time `json:"occurred_at"`

	// Data is the domain payload, JSON-encoded on the wire. On a consumed event
	// it holds the raw JSON; use DecodeData to unmarshal it into a concrete type.
	Data any `json:"data"`
}