event

type Envelope struct {
	// ID is a ULID: lexically sortable, globally unique, minted once at
	// command time.
	ID string `json:"id"`

	// TenantID scopes the event; consumers must never re-derive it from
	// the payload.
	TenantID string `json:"tenant_id"`

	// ScopeID is the optional secondary scope (sub-tenant partition). Empty when
	// unscoped. Carried so projections can stamp scope_id on derived rows.
	ScopeID string `json:"scopeId,omitempty"`

	// Aggregate is the registry entity name, e.g. "asset".
	Aggregate string `json:"aggregate"`

	// AggID identifies the aggregate instance.
	AggID string `json:"agg_id"`

	// Version is the aggregate's monotonic version after this event.
	Version int64 `json:"version"`

	// Type is the derived event type, e.g. "asset.updated".
	Type string `json:"type"`

	// At is the commit-side timestamp.
	At time.Time `json:"at"`

	// PayloadSchemaVersion versions the payload shape; upcasters migrate
	// old shapes forward at decode.
	PayloadSchemaVersion int `json:"payload_schema_version"`

	// Payload is the column-keyed JSON of the aggregate after the change
	// (empty object for deletes).
	Payload json.RawMessage `json:"payload"`

	// Traceparent is the W3C traceparent active when the command executed.
	Traceparent string `json:"traceparent,omitempty"`
}

type Publisher interface {
	Publish(ctx context.Context, env Envelope, channels []string) (streamID string, err error)
}

type Upcaster struct {
	Type        string
	FromVersion int
	Fn          func(json.RawMessage) (json.RawMessage, error)
}

type UpcasterChain struct {
	// contains filtered or unexported fields
}