fix:补充echo测试代码

lib/talk/startChart/entity/scp_message.dart

@@ -260,7 +260,8 @@ class ScpMessage {
     } else {
       throw FormatException("Invalid PayloadLength length");
     }
-    // print("message result: $message");
+    print(
+        "======================messageId: ${message.MessageId}, spTotal: ${message.SpTotal}, spIndex: ${message.SpIndex}, payloadType: ${message.PayloadType}, payloadLength: ${message.PayloadLength}");
 
     // 处理其他类型的Payload
     if (message.PayloadLength != null &&
@@ -526,8 +527,6 @@ class ScpMessage {
     required List<int> byte,
     required int payloadType,
   }) {
-    // print(
-    //     '_handleFragmentedPayload spTotal:$spTotal spindex:$spIndex} byte:${byte.take(20)}');
     // 初始化分包列表
     if (!_packetBuffer.containsKey(messageId)) {
       _packetBuffer[messageId] = List.filled(spTotal, []);
@@ -549,13 +548,10 @@ class ScpMessage {
         // 解析完整的 payload
         final TalkData talkData = TalkData.fromBuffer(completePayload);
         return talkData;
+      } else {
+        String payload = utf8.decode(completePayload);
+        return payload;
       }
-
-      return completePayload;
-
-      // 解析完整的 payload
-      // final TalkData talkData = TalkData.fromBuffer(completePayload);
-      // String payload = utf8.decode(completePayload);
     } else {
       // 如果分包尚未接收完全，返回 null 或其他指示符
       return null;

lib/talk/startChart/handle/impl/udp_echo_test_handler.dart

@@ -19,10 +19,11 @@ class UdpEchoTestHandler extends ScpMessageBaseHandle
     // TODO: 收到回声测试回复
     final List<int> payload = scpMessage.Payload;
 
-    talkDataRepository.addTalkData(
-        TalkData(content: payload, contentType: TalkData_ContentTypeE.Image));
     if (payload is String) {
       EasyLoading.showToast(scpMessage.Payload, duration: 2000.milliseconds);
+    } else {
+      talkDataRepository.addTalkData(
+          TalkData(content: payload, contentType: TalkData_ContentTypeE.Image));
     }
   }