fix: MetadataReceived event parameters bug

Author: LichKing-2234

Callback.swift

@@ -17,14 +17,14 @@ protocol Callback: class {
 }
 
 extension Callback {
-    func code(_ code: Int32?, _ runnable: ((Int32) -> Any?)? = nil) {
+    func code(_ code: Int32?, _ runnable: ((Int32?) -> Any?)? = nil) {
         if code == nil || code! < 0 {
             let newCode = abs(Int(code ?? Int32(AgoraErrorCode.notInitialized.rawValue)))
             failure(String(newCode), AgoraRtcEngineKit.getErrorDescription(newCode) ?? "")
             return
         }
 
-        let res = runnable?(code!)
+        let res = runnable?(code)
         if res is Void {
             success(nil)
         } else {

MediaObserver.swift

@@ -43,9 +43,7 @@ extension MediaObserver: AgoraMediaMetadataDataSource {
 extension MediaObserver: AgoraMediaMetadataDelegate {
     func receiveMetadata(_ data: Data, fromUser uid: Int, atTimestamp timestamp: TimeInterval) {
         emitter([
-            "buffer": String(data: data, encoding: .utf8),
-            "uid": uid,
-            "timeStampMs": timestamp
+            "data": [String(data: data, encoding: .utf8) ?? "", uid, timestamp]
         ])
     }
 }