Add error and close callbacks to Swift Realtime service

This change adds support for custom error and close event handlers in the Swift Realtime implementation. Developers can now register callbacks to be notified when connection errors occur or when the connection closes, enabling better error handling and connection state management in applications.

Author: ChiragAgg5k

templates/swift/Sources/Services/Realtime.swift.twig

@@ -22,6 +22,17 @@ open class Realtime : Service {
     private var reconnectAttempts = 0
     private var subscriptionsCounter = 0
     private var reconnect = true
+    
+    private var onErrorCallback: ((Swift.Error?, HTTPResponseStatus?) -> Void)?
+    private var onCloseCallback: (() -> Void)?
+
+    public func onError(_ callback: @escaping (Swift.Error?, HTTPResponseStatus?) -> Void) {
+        self.onErrorCallback = callback
+    }
+    
+    public func onClose(_ callback: @escaping () -> Void) {
+        self.onCloseCallback = callback
+    }
 
     private func startHeartbeat() {
         stopHeartbeat()
@@ -211,6 +222,8 @@ extension Realtime: WebSocketClientDelegate {
     public func onClose(channel: Channel, data: Data) async throws {
         stopHeartbeat()
 
+        onCloseCallback?()
+
         if (!reconnect) {
             reconnect = true
             return
@@ -230,6 +243,8 @@ extension Realtime: WebSocketClientDelegate {
     public func onError(error: Swift.Error?, status: HTTPResponseStatus?) {
         stopHeartbeat()
         print(error?.localizedDescription ?? "Unknown error")
+
+        onErrorCallback?(error, status)
     }
 
     func handleResponseError(from json: [String: Any]) throws {