fix quic

Tun/Punchnet/Actors/SDLQuicClient.swift

@@ -116,13 +116,18 @@ actor SDLQUICReader {
     
     func start() {
         self.readTask = Task {
-            var buffer: ByteBuffer = allocator.buffer(capacity: self.maxBufferSize)
+            var buffer = allocator.buffer(capacity: self.maxBufferSize)
+            let threshold = self.maxBufferSize / 10 * 6
             do {
                 while !Task.isCancelled {
                     let (isComplete, data) = try await self.readOnce()
                     if let data, !data.isEmpty {
                         buffer.writeBytes(data)
                         let frames = try parseFrames(buffer: &buffer)
+                        if buffer.readerIndex > threshold {
+                            buffer.discardReadBytes()
+                        }
+                        
                         for frame in frames {
                             if let message = SDLQUICCodec.decode(frame: frame) {
                                 self.messageCont.yield(message)
@@ -166,11 +171,7 @@ actor SDLQUICReader {
                 frames.append(buf)
             }
         }
-        
-        if buffer.readerIndex > maxBufferSize / 10 * 6 {
-            buffer.discardReadBytes()
-        }
-        
+    
         return frames
     }