feat: distribute new local posts to followers via websocket

internal/streaming/event.go

@@ -5,10 +5,20 @@ import "encoding/json"
 type EventType int8
 
 const (
+	// Sent when an error occurs
+	// Payload: {code:int, message:string}
 	EventTypeError EventType = 1
-	EventTypePost  EventType = 2
+	// Sent when echoing back received messages
+	// Payload: <received message>
+	EventTypeEcho EventType = 2
+	// Sent on a new post being created
+	// Payload: <post object>
+	EventTypePost EventType = 3
 
-	EventTypeSubscribe   EventType = 126
+	// Receive events
+	// Subscribe to a new event
+	EventTypeSubscribe EventType = 126
+	// Unsubscribe from an event
 	EventTypeUnsubscribe EventType = 127
 )
 
@@ -16,6 +26,8 @@ func (et EventType) Valid() bool {
 	switch et {
 	case EventTypeError:
 		return true
+	case EventTypeEcho:
+		return true
 	case EventTypePost:
 		return true
 	case EventTypeSubscribe: